diff --git a/change/@fluentui-react-tree-6759724f-a9fe-45df-81be-ec6cb8f2fe98.json b/change/@fluentui-react-tree-6759724f-a9fe-45df-81be-ec6cb8f2fe98.json
new file mode 100644
index 00000000000000..717989763b386b
--- /dev/null
+++ b/change/@fluentui-react-tree-6759724f-a9fe-45df-81be-ec6cb8f2fe98.json
@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "feat: implements nested tree selection",
+  "packageName": "@fluentui/react-tree",
+  "email": "bernardo.sunderhus@gmail.com",
+  "dependentChangeType": "patch"
+}
diff --git a/packages/react-components/react-tree/etc/react-tree.api.md b/packages/react-components/react-tree/etc/react-tree.api.md
index 312b199f750541..41d33e4ebdc201 100644
--- a/packages/react-components/react-tree/etc/react-tree.api.md
+++ b/packages/react-components/react-tree/etc/react-tree.api.md
@@ -79,12 +79,15 @@ export type HeadlessFlatTreeItem<Props extends HeadlessFlatTreeItemProps> = Head
 export type HeadlessFlatTreeItemProps = HeadlessTreeItemProps;
 
 // @public (undocumented)
-export type HeadlessFlatTreeOptions = Pick<FlatTreeProps, 'onOpenChange' | 'onNavigation_unstable' | 'selectionMode' | 'onCheckedChange'> & Pick<TreeProps, 'defaultOpenItems' | 'openItems' | 'checkedItems' | 'defaultChecked'>;
+export type HeadlessFlatTreeOptions = Pick<FlatTreeProps, 'onOpenChange' | 'onNavigation_unstable' | 'selectionMode' | 'onCheckedChange'> & Pick<TreeProps, 'defaultOpenItems' | 'openItems' | 'checkedItems'> & {
+    defaultCheckedItems?: TreeProps['checkedItems'];
+};
+
+// @public (undocumented)
+export const renderFlatTree_unstable: (state: TreeState, contextValues: TreeContextValues) => JSX.Element;
 
 // @public (undocumented)
-const renderTree_unstable: (state: TreeState, contextValues: TreeContextValues) => JSX.Element;
-export { renderTree_unstable as renderFlatTree_unstable }
-export { renderTree_unstable }
+export const renderTree_unstable: (state: TreeState, contextValues: TreeContextValues) => JSX.Element;
 
 // @public
 export const renderTreeItem_unstable: (state: TreeItemState, contextValues: TreeItemContextValues) => JSX.Element;
@@ -153,7 +156,7 @@ export type TreeItemContextValue = {
     itemType: TreeItemType;
     value: TreeItemValue;
     open: boolean;
-    checked?: TreeSelectionValue;
+    checked: TreeSelectionValue;
 };
 
 // @public
@@ -304,7 +307,6 @@ export type TreeProps = ComponentProps<TreeSlots> & {
     onNavigation_unstable?(event: TreeNavigationEvent_unstable, data: TreeNavigationData_unstable): void;
     selectionMode?: SelectionMode_2;
     checkedItems?: Iterable<TreeItemValue | [TreeItemValue, TreeSelectionValue]>;
-    defaultCheckedItems?: Iterable<TreeItemValue | [TreeItemValue, TreeSelectionValue]>;
     onCheckedChange?(event: TreeCheckedChangeEvent, data: TreeCheckedChangeData): void;
 };
 
@@ -331,6 +333,9 @@ export { TreeState }
 // @public (undocumented)
 export const useFlatTree_unstable: (props: FlatTreeProps, ref: React_2.Ref<HTMLElement>) => TreeState;
 
+// @public (undocumented)
+export const useFlatTreeContextValues_unstable: (state: TreeState) => TreeContextValues;
+
 // @public (undocumented)
 export const useFlatTreeStyles_unstable: (state: TreeState) => TreeState;
 
@@ -344,9 +349,7 @@ export const useTree_unstable: (props: TreeProps, ref: React_2.Ref<HTMLElement>)
 export const useTreeContext_unstable: <T>(selector: ContextSelector<TreeContextValue, T>) => T;
 
 // @public (undocumented)
-function useTreeContextValues_unstable(state: TreeState): TreeContextValues;
-export { useTreeContextValues_unstable as useFlatTreeContextValues_unstable }
-export { useTreeContextValues_unstable }
+export function useTreeContextValues_unstable(state: TreeState): TreeContextValues;
 
 // @public
 export function useTreeItem_unstable(props: TreeItemProps, ref: React_2.Ref<HTMLDivElement>): TreeItemState;
diff --git a/packages/react-components/react-tree/src/components/FlatTree/FlatTree.cy.tsx b/packages/react-components/react-tree/src/components/FlatTree/FlatTree.cy.tsx
index 22fc40085f6fd9..dad6f5bc2851e3 100644
--- a/packages/react-components/react-tree/src/components/FlatTree/FlatTree.cy.tsx
+++ b/packages/react-components/react-tree/src/components/FlatTree/FlatTree.cy.tsx
@@ -1,3 +1,6 @@
+/// <reference types="cypress" />
+/// <reference types="cypress-real-events" />
+
 import * as React from 'react';
 import { mount as mountBase } from '@cypress/react';
 import { FluentProvider } from '@fluentui/react-provider';
@@ -60,7 +63,7 @@ const TreeTest: React.FC<FlatTreeProps & HeadlessFlatTreeOptions> = props => {
     props,
   );
   return (
-    <FlatTree {...props} {...flatTree.getTreeProps()} id="baseTree" aria-label="Tree">
+    <FlatTree {...props} {...flatTree.getTreeProps()} id="tree" aria-label="Tree">
       {Array.from(flatTree.items(), item => (
         <TreeItem key={item.value} {...item.getTreeItemProps()} />
       ))}
@@ -69,7 +72,7 @@ const TreeTest: React.FC<FlatTreeProps & HeadlessFlatTreeOptions> = props => {
 };
 TreeTest.displayName = 'FlatTree';
 
-describe(TreeTest.displayName!, () => {
+describe('FlatTree', () => {
   it('should have all but first level items hidden', () => {
     mount(<TreeTest />);
     cy.get('[data-testid="item1__item1"]').should('not.exist');
@@ -125,7 +128,7 @@ describe(TreeTest.displayName!, () => {
     });
     it('should not expand/collapse item on actions click', () => {
       mount(
-        <TreeTest id="baseTree" aria-label="Tree">
+        <TreeTest id="tree" aria-label="Tree">
           <TreeItem itemType="branch" value="item1" data-testid="item1">
             <TreeItemLayout actions={<Button id="action">action!</Button>}>level 1, item 1</TreeItemLayout>
             <Tree>
@@ -141,6 +144,12 @@ describe(TreeTest.displayName!, () => {
       cy.get(`#action`).realClick();
       cy.get('[data-testid="item1__item1"]').should('not.exist');
     });
+    it('should select item on selector click', () => {
+      mount(<TreeTest selectionMode="single" />);
+      cy.get('[data-testid="item1"]').should('not.have.attr', 'aria-selected', 'true');
+      cy.get(`[data-testid="item1"] .${treeItemLayoutClassNames.selector}`).realClick();
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-selected', 'true');
+    });
   });
   describe('Keyboard interactions', () => {
     it('should expand/collapse item on Enter key', () => {
@@ -168,7 +177,7 @@ describe(TreeTest.displayName!, () => {
     });
     it('should focus on actions when pressing tab key', () => {
       mount(
-        <TreeTest id="baseTree" aria-label="Tree">
+        <TreeTest id="tree" aria-label="Tree">
           <TreeItem itemType="branch" value="item1" data-testid="item1">
             <TreeItemLayout actions={<Button id="action">action</Button>}>level 1, item 1</TreeItemLayout>
             <Tree>
@@ -187,7 +196,7 @@ describe(TreeTest.displayName!, () => {
     });
     it('should not expand/collapse item on actions Enter/Space key', () => {
       mount(
-        <TreeTest id="baseTree" aria-label="Tree">
+        <TreeTest id="tree" aria-label="Tree">
           <TreeItem itemType="branch" value="item1" data-testid="item1">
             <TreeItemLayout actions={<Button id="action">action</Button>}>level 1, item 1</TreeItemLayout>
             <Tree>
@@ -213,7 +222,7 @@ describe(TreeTest.displayName!, () => {
       cy.document().realPress('Tab');
       cy.get('[data-testid="item1"]').should('be.focused');
     });
-    it('should focus out of baseTree when pressing tab key inside baseTree.', () => {
+    it('should focus out of tree when pressing tab key inside tree.', () => {
       mount(<TreeTest />);
       cy.focused().should('not.exist');
       cy.document().realPress('Tab');
@@ -249,5 +258,106 @@ describe(TreeTest.displayName!, () => {
         cy.get('[data-testid="item1"]').should('be.focused');
       });
     });
+    it('should select item on Space key', () => {
+      mount(<TreeTest selectionMode="single" />);
+      cy.get('[data-testid="item1"]').should('not.have.attr', 'aria-selected', 'true');
+      cy.get(`[data-testid="item1"]`).focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-selected', 'true');
+    });
+  });
+  describe('single selection', () => {
+    it('should switch selection between items', () => {
+      mount(<TreeTest selectionMode="single" />);
+      cy.get('[data-testid="item1"]').should('not.have.attr', 'aria-selected', 'true');
+      cy.get('[data-testid="item2"]').should('not.have.attr', 'aria-selected', 'true');
+      cy.get(`[data-testid="item1"]`).focus().realPress('Space');
+      cy.get(`[data-testid="item2"]`).focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('not.have.attr', 'aria-selected', 'true');
+      cy.get('[data-testid="item2"]').should('have.attr', 'aria-selected', 'true');
+    });
+    it('should render with a default selected item', () => {
+      mount(<TreeTest selectionMode="single" defaultCheckedItems={['item1']} />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-selected', 'true');
+    });
+    it('should maintain selection when closing and reopening a branch', () => {
+      mount(<TreeTest selectionMode="single" defaultOpenItems={['item1']} defaultCheckedItems={['item1__item1']} />);
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-selected', 'true');
+      cy.get('[data-testid="item1"]').focus().realPress('{enter}');
+      cy.get('[data-testid="item1__item1"]').should('not.exist');
+      cy.get('[data-testid="item1"]').focus().realPress('{enter}');
+      cy.get('[data-testid="item1__item1"]').should('exist');
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-selected', 'true');
+    });
+  });
+  describe('multiple selection', () => {
+    it('should select multiple items', () => {
+      mount(<TreeTest selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('not.have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item2"]').should('not.have.attr', 'aria-checked', 'true');
+      cy.get(`[data-testid="item1"]`).focus().realPress('Space');
+      cy.get(`[data-testid="item2"]`).focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item2"]').should('have.attr', 'aria-checked', 'true');
+    });
+    it('should have multiple items default selected', () => {
+      mount(<TreeTest defaultCheckedItems={['item1', 'item2']} selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item2"]').should('have.attr', 'aria-checked', 'true');
+    });
+    it('should select all children when selecting a parent', () => {
+      mount(<TreeTest defaultCheckedItems={['item1']} defaultOpenItems={['item1']} selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item1__item2"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item1__item3"]').should('have.attr', 'aria-checked', 'true');
+    });
+    it('should deselect all children when deselecting a parent', () => {
+      mount(<TreeTest defaultCheckedItems={['item1']} defaultOpenItems={['item1']} selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'false');
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-checked', 'false');
+      cy.get('[data-testid="item1__item2"]').should('have.attr', 'aria-checked', 'false');
+      cy.get('[data-testid="item1__item3"]').should('have.attr', 'aria-checked', 'false');
+    });
+    it('should deselect parent when deselecting all children', () => {
+      mount(<TreeTest defaultCheckedItems={['item1']} defaultOpenItems={['item1']} selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item1__item1"]').focus().realPress('Space');
+      cy.get('[data-testid="item1__item2"]').focus().realPress('Space');
+      cy.get('[data-testid="item1__item3"]').focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'false');
+    });
+    it('should select parent when selecting all children', () => {
+      mount(<TreeTest defaultOpenItems={['item1']} selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'false');
+      cy.get('[data-testid="item1__item1"]').focus().realPress('Space');
+      cy.get('[data-testid="item1__item2"]').focus().realPress('Space');
+      cy.get('[data-testid="item1__item3"]').focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'true');
+    });
+    it('parent should be indeterminate when selecting some children', () => {
+      mount(<TreeTest defaultOpenItems={['item1']} selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'false');
+      cy.get('[data-testid="item1__item1"]').focus().realPress('Space');
+      cy.get('[data-testid="item1__item2"]').focus().realPress('Space');
+      cy.get('[data-testid="item1"]').should('not.have.attr', 'aria-checked', 'false');
+    });
+    it('should maintain selection when closing and reopening a branch', () => {
+      mount(
+        <TreeTest selectionMode="multiselect" defaultOpenItems={['item1']} defaultCheckedItems={['item1__item1']} />,
+      );
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-checked', 'true');
+      cy.get('[data-testid="item1"]').focus().realPress('{enter}');
+      cy.get('[data-testid="item1__item1"]').should('not.exist');
+      cy.get('[data-testid="item1"]').focus().realPress('{enter}');
+      cy.get('[data-testid="item1__item1"]').should('exist');
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-checked', 'true');
+    });
+    it('should change selection when selecting a closed branch', () => {
+      mount(<TreeTest selectionMode="multiselect" />);
+      cy.get('[data-testid="item1"]').should('have.attr', 'aria-checked', 'false');
+      cy.get('[data-testid="item1"]').focus().realPress('Space').realPress('{enter}');
+      cy.get('[data-testid="item1__item1"]').should('have.attr', 'aria-checked', 'true');
+    });
   });
 });
diff --git a/packages/react-components/react-tree/src/components/FlatTree/FlatTree.tsx b/packages/react-components/react-tree/src/components/FlatTree/FlatTree.tsx
index 0aad4662e9ca92..04e7cf7246e439 100644
--- a/packages/react-components/react-tree/src/components/FlatTree/FlatTree.tsx
+++ b/packages/react-components/react-tree/src/components/FlatTree/FlatTree.tsx
@@ -1,12 +1,10 @@
 import * as React from 'react';
 import type { ForwardRefComponent } from '@fluentui/react-utilities';
 import type { FlatTreeProps } from './FlatTree.types';
-import {
-  useTreeContextValues_unstable as useFlatTreeContextValues_unstable,
-  renderTree_unstable as renderFlatTree_unstable,
-} from '../Tree/index';
 import { useFlatTree_unstable } from './useFlatTree';
 import { useFlatTreeStyles_unstable } from './useFlatTreeStyles.styles';
+import { useFlatTreeContextValues_unstable } from './useFlatTreeContextValues';
+import { renderFlatTree_unstable } from './renderFlatTree';
 
 /**
  * FlatTree component - TODO: add more docs
diff --git a/packages/react-components/react-tree/src/components/FlatTree/index.ts b/packages/react-components/react-tree/src/components/FlatTree/index.ts
index 30ad76d7e65fc3..c6dd8973d6fcf0 100644
--- a/packages/react-components/react-tree/src/components/FlatTree/index.ts
+++ b/packages/react-components/react-tree/src/components/FlatTree/index.ts
@@ -1,9 +1,7 @@
 export * from './FlatTree';
 export * from './FlatTree.types';
-export {
-  renderTree_unstable as renderFlatTree_unstable,
-  useTreeContextValues_unstable as useFlatTreeContextValues_unstable,
-} from '../Tree/index';
 export * from './useHeadlessFlatTree';
 export * from './useFlatTree';
 export * from './useFlatTreeStyles.styles';
+export * from './useFlatTreeContextValues';
+export * from './renderFlatTree';
diff --git a/packages/react-components/react-tree/src/components/FlatTree/renderFlatTree.ts b/packages/react-components/react-tree/src/components/FlatTree/renderFlatTree.ts
new file mode 100644
index 00000000000000..31612c99163eef
--- /dev/null
+++ b/packages/react-components/react-tree/src/components/FlatTree/renderFlatTree.ts
@@ -0,0 +1,5 @@
+import { TreeContextValues, renderTree_unstable } from '../../Tree';
+import type { FlatTreeState } from './FlatTree.types';
+
+export const renderFlatTree_unstable: (state: FlatTreeState, contextValues: TreeContextValues) => JSX.Element =
+  renderTree_unstable;
diff --git a/packages/react-components/react-tree/src/components/FlatTree/useFlatControllableCheckedItems.ts b/packages/react-components/react-tree/src/components/FlatTree/useFlatControllableCheckedItems.ts
index bbb28a1adf70ea..67834fdd4132ca 100644
--- a/packages/react-components/react-tree/src/components/FlatTree/useFlatControllableCheckedItems.ts
+++ b/packages/react-components/react-tree/src/components/FlatTree/useFlatControllableCheckedItems.ts
@@ -4,27 +4,32 @@ import { ImmutableMap } from '../../utils/ImmutableMap';
 import * as React from 'react';
 import type { HeadlessTree, HeadlessTreeItemProps } from '../../utils/createHeadlessTree';
 import { createCheckedItems } from '../../utils/createCheckedItems';
-import type { TreeCheckedChangeData, TreeProps } from '../Tree/Tree.types';
+import type { TreeCheckedChangeData } from '../Tree/Tree.types';
+import { HeadlessFlatTreeOptions } from './useHeadlessFlatTree';
 
-export function useFlatControllableCheckedItems(props: Pick<TreeProps, 'checkedItems' | 'defaultCheckedItems'>) {
-  const [checkedItems, setCheckedItems] = useControllableState({
+export function useFlatControllableCheckedItems<Props extends HeadlessTreeItemProps>(
+  props: Pick<HeadlessFlatTreeOptions, 'checkedItems' | 'defaultCheckedItems' | 'selectionMode'>,
+  headlessTree: HeadlessTree<Props>,
+) {
+  return useControllableState({
     initialState: ImmutableMap.empty,
-    state: React.useMemo(() => props.checkedItems && createCheckedItems(props.checkedItems), [props.checkedItems]),
-    defaultState: () => createCheckedItems(props.defaultCheckedItems),
+    state: React.useMemo(
+      () => (props.selectionMode ? props.checkedItems && createCheckedItems(props.checkedItems) : undefined),
+      [props.checkedItems, props.selectionMode],
+    ),
+    defaultState: () => initializeCheckedItems(props, headlessTree),
   });
-
-  return [checkedItems, setCheckedItems] as const;
 }
 
-export function createNextFlatCheckedItems<Props extends HeadlessTreeItemProps>(
+export function createNextFlatCheckedItems(
   data: Pick<TreeCheckedChangeData, 'value' | 'checked' | 'selectionMode'>,
   previousCheckedItems: ImmutableMap<TreeItemValue, 'mixed' | boolean>,
-  virtualTree: HeadlessTree<Props>,
+  headlessTree: HeadlessTree<HeadlessTreeItemProps>,
 ): ImmutableMap<TreeItemValue, 'mixed' | boolean> {
   if (data.selectionMode === 'single') {
     return ImmutableMap.create([[data.value, data.checked]]);
   }
-  const treeItem = virtualTree.get(data.value);
+  const treeItem = headlessTree.get(data.value);
   if (!treeItem) {
     if (process.env.NODE_ENV !== 'production') {
       // eslint-disable-next-line no-console
@@ -33,20 +38,20 @@ export function createNextFlatCheckedItems<Props extends HeadlessTreeItemProps>(
     return previousCheckedItems;
   }
   const nextCheckedItems = new Map(previousCheckedItems);
-  for (const children of virtualTree.subtree(data.value)) {
+  for (const children of headlessTree.subtree(data.value)) {
     nextCheckedItems.set(children.value, data.checked);
   }
   nextCheckedItems.set(data.value, data.checked);
 
   let isAncestorsMixed = false;
-  for (const parent of virtualTree.ancestors(treeItem.value)) {
+  for (const parent of headlessTree.ancestors(treeItem.value)) {
     // if one parent is mixed, all ancestors are mixed
     if (isAncestorsMixed) {
       nextCheckedItems.set(parent.value, 'mixed');
       continue;
     }
     const checkedChildren = [];
-    for (const child of virtualTree.children(parent.value)) {
+    for (const child of headlessTree.children(parent.value)) {
       if ((nextCheckedItems.get(child.value) ?? false) === data.checked) {
         checkedChildren.push(child);
       }
@@ -61,3 +66,19 @@ export function createNextFlatCheckedItems<Props extends HeadlessTreeItemProps>(
   }
   return ImmutableMap.dangerouslyCreate_unstable(nextCheckedItems);
 }
+
+function initializeCheckedItems(
+  props: Pick<HeadlessFlatTreeOptions, 'selectionMode' | 'defaultCheckedItems'>,
+  headlessTree: HeadlessTree<HeadlessTreeItemProps>,
+) {
+  if (!props.selectionMode) {
+    return ImmutableMap.empty;
+  }
+  let state = createCheckedItems(props.defaultCheckedItems);
+  if (props.selectionMode === 'multiselect') {
+    for (const [value, checked] of state) {
+      state = createNextFlatCheckedItems({ value, checked, selectionMode: props.selectionMode }, state, headlessTree);
+    }
+  }
+  return state;
+}
diff --git a/packages/react-components/react-tree/src/components/FlatTree/useFlatTreeContextValues.ts b/packages/react-components/react-tree/src/components/FlatTree/useFlatTreeContextValues.ts
new file mode 100644
index 00000000000000..fe215c0357c5f3
--- /dev/null
+++ b/packages/react-components/react-tree/src/components/FlatTree/useFlatTreeContextValues.ts
@@ -0,0 +1,5 @@
+import { TreeContextValues, useTreeContextValues_unstable } from '../../Tree';
+import type { FlatTreeState } from './FlatTree.types';
+
+export const useFlatTreeContextValues_unstable: (state: FlatTreeState) => TreeContextValues =
+  useTreeContextValues_unstable;
diff --git a/packages/react-components/react-tree/src/components/FlatTree/useHeadlessFlatTree.ts b/packages/react-components/react-tree/src/components/FlatTree/useHeadlessFlatTree.ts
index 51b3fdecf9b993..72c5376c5fb929 100644
--- a/packages/react-components/react-tree/src/components/FlatTree/useHeadlessFlatTree.ts
+++ b/packages/react-components/react-tree/src/components/FlatTree/useHeadlessFlatTree.ts
@@ -95,7 +95,9 @@ export type HeadlessFlatTreeOptions = Pick<
   FlatTreeProps,
   'onOpenChange' | 'onNavigation_unstable' | 'selectionMode' | 'onCheckedChange'
 > &
-  Pick<TreeProps, 'defaultOpenItems' | 'openItems' | 'checkedItems' | 'defaultChecked'>;
+  Pick<TreeProps, 'defaultOpenItems' | 'openItems' | 'checkedItems'> & {
+    defaultCheckedItems?: TreeProps['checkedItems'];
+  };
 
 /**
  * this hook provides FlatTree API to manage all required mechanisms to convert a list of items into renderable TreeItems
@@ -115,7 +117,7 @@ export function useHeadlessFlatTree_unstable<Props extends HeadlessTreeItemProps
 ): HeadlessFlatTree<Props> {
   const headlessTree = React.useMemo(() => createHeadlessTree(props), [props]);
   const [openItems, setOpenItems] = useControllableOpenItems(options);
-  const [checkedItems, setCheckedItems] = useFlatControllableCheckedItems(options);
+  const [checkedItems, setCheckedItems] = useFlatControllableCheckedItems(options, headlessTree);
   const { initialize, navigate } = useFlatTreeNavigation(headlessTree);
   const walkerRef = React.useRef<HTMLElementWalker>();
   const initializeWalker = React.useCallback(
@@ -130,13 +132,21 @@ export function useHeadlessFlatTree_unstable<Props extends HeadlessTreeItemProps
 
   const treeRef = React.useRef<HTMLDivElement>(null);
   const handleOpenChange = useEventCallback((event: TreeOpenChangeEvent, data: TreeOpenChangeData) => {
-    options.onOpenChange?.(event, data);
-    setOpenItems(createNextOpenItems(data, openItems));
+    const nextOpenItems = createNextOpenItems(data, openItems);
+    options.onOpenChange?.(event, {
+      ...data,
+      openItems: nextOpenItems.dangerouslyGetInternalSet_unstable(),
+    });
+    setOpenItems(nextOpenItems);
   });
 
   const handleCheckedChange = useEventCallback((event: TreeCheckedChangeEvent, data: TreeCheckedChangeData) => {
-    options.onCheckedChange?.(event, data);
-    setCheckedItems(createNextFlatCheckedItems(data, checkedItems, headlessTree));
+    const nextCheckedItems = createNextFlatCheckedItems(data, checkedItems, headlessTree);
+    options.onCheckedChange?.(event, {
+      ...data,
+      checkedItems: nextCheckedItems.dangerouslyGetInternalMap_unstable(),
+    });
+    setCheckedItems(nextCheckedItems);
   });
 
   const handleNavigation = useEventCallback(
diff --git a/packages/react-components/react-tree/src/components/Tree/Tree.cy.tsx b/packages/react-components/react-tree/src/components/Tree/Tree.cy.tsx
index cbd560b1de6b1e..4e4a539383849f 100644
--- a/packages/react-components/react-tree/src/components/Tree/Tree.cy.tsx
+++ b/packages/react-components/react-tree/src/components/Tree/Tree.cy.tsx
@@ -1,3 +1,6 @@
+/// <reference types="cypress" />
+/// <reference types="cypress-real-events" />
+
 import * as React from 'react';
 import { mount as mountBase } from '@cypress/react';
 import { FluentProvider } from '@fluentui/react-provider';
@@ -18,7 +21,7 @@ const mount = (element: JSX.Element) => {
 
 const TreeTest: React.FC<TreeProps> = props => {
   return (
-    <Tree id="baseTree" aria-label="Tree" {...props}>
+    <Tree id="tree" aria-label="Tree" {...props}>
       {props.children ?? (
         <>
           <TreeItem itemType="branch" value="item1" data-testid="item1">
@@ -55,7 +58,7 @@ const TreeTest: React.FC<TreeProps> = props => {
 };
 TreeTest.displayName = 'Tree';
 
-describe(TreeTest.displayName!, () => {
+describe('Tree', () => {
   it('should have all but first level items hidden', () => {
     mount(<TreeTest />);
     cy.get('[data-testid="item1__item1"]').should('not.exist');
@@ -111,7 +114,7 @@ describe(TreeTest.displayName!, () => {
     });
     it('should not expand/collapse item on actions click', () => {
       mount(
-        <TreeTest id="baseTree" aria-label="Tree">
+        <TreeTest id="tree" aria-label="Tree">
           <TreeItem itemType="branch" value="item1" data-testid="item1">
             <TreeItemLayout actions={<Button id="action">action!</Button>}>level 1, item 1</TreeItemLayout>
             <Tree>
@@ -154,7 +157,7 @@ describe(TreeTest.displayName!, () => {
     });
     it('should focus on actions when pressing tab key', () => {
       mount(
-        <TreeTest id="baseTree" aria-label="Tree">
+        <TreeTest id="tree" aria-label="Tree">
           <TreeItem itemType="branch" value="item1" data-testid="item1">
             <TreeItemLayout actions={<Button id="action">action</Button>}>level 1, item 1</TreeItemLayout>
             <Tree>
@@ -173,7 +176,7 @@ describe(TreeTest.displayName!, () => {
     });
     it('should not expand/collapse item on actions Enter/Space key', () => {
       mount(
-        <TreeTest id="baseTree" aria-label="Tree">
+        <TreeTest id="tree" aria-label="Tree">
           <TreeItem itemType="branch" value="item1" data-testid="item1">
             <TreeItemLayout actions={<Button id="action">action</Button>}>level 1, item 1</TreeItemLayout>
             <Tree>
@@ -199,7 +202,7 @@ describe(TreeTest.displayName!, () => {
       cy.document().realPress('Tab');
       cy.get('[data-testid="item1"]').should('be.focused');
     });
-    it('should focus out of baseTree when pressing tab key inside baseTree.', () => {
+    it('should focus out of tree when pressing tab key inside tree.', () => {
       mount(<TreeTest />);
       cy.focused().should('not.exist');
       cy.document().realPress('Tab');
diff --git a/packages/react-components/react-tree/src/components/Tree/Tree.types.ts b/packages/react-components/react-tree/src/components/Tree/Tree.types.ts
index 8783a4bdeb6b47..242f3ef9f63bab 100644
--- a/packages/react-components/react-tree/src/components/Tree/Tree.types.ts
+++ b/packages/react-components/react-tree/src/components/Tree/Tree.types.ts
@@ -129,11 +129,6 @@ export type TreeProps = ComponentProps<TreeSlots> & {
    * These property is ignored for subtrees.
    */
   checkedItems?: Iterable<TreeItemValue | [TreeItemValue, TreeSelectionValue]>;
-  /**
-   * This refers to a list of ids of default checked items, or a list of tuples of ids and checked state.
-   * These property is ignored for subtrees.
-   */
-  defaultCheckedItems?: Iterable<TreeItemValue | [TreeItemValue, TreeSelectionValue]>;
   /**
    * Callback fired when the component changes value from checked state.
    * These property is ignored for subtrees.
diff --git a/packages/react-components/react-tree/src/components/Tree/useControllableCheckedItems.ts b/packages/react-components/react-tree/src/components/Tree/useControllableCheckedItems.ts
deleted file mode 100644
index 81f539570c33d9..00000000000000
--- a/packages/react-components/react-tree/src/components/Tree/useControllableCheckedItems.ts
+++ /dev/null
@@ -1,106 +0,0 @@
-import { useControllableState } from '@fluentui/react-utilities';
-import * as React from 'react';
-import type { TreeProps } from './Tree.types';
-import { ImmutableMap } from '../../utils/ImmutableMap';
-import { createCheckedItems } from '../../utils/createCheckedItems';
-
-export type ControllableCheckedItemsOptions = {
-  checkedItems?: TreeProps['checkedItems'];
-  defaultCheckedItems?: TreeProps['checkedItems'];
-};
-
-export function useControllableCheckedItems(props: ControllableCheckedItemsOptions) {
-  return useControllableState({
-    initialState: ImmutableMap.empty,
-    state: React.useMemo(() => props.checkedItems && createCheckedItems(props.checkedItems), [props.checkedItems]),
-    defaultState: () => createCheckedItems(props.defaultCheckedItems),
-  });
-}
-
-// export function useCheckedItemsState(props: Pick<TreeProps, 'checkedItems' | 'defaultCheckedItems' | 'selectionMode'>) {
-//   const [walkerRef, rootRef] = useHTMLElementWalkerRef(treeItemFilter);
-//   const selections = React.useMemo(() => initializeSelection(props.checkedItems ?? []), [props.checkedItems]);
-//   const defaultSelections = React.useMemo(
-//     () => initializeSelection(props.defaultCheckedItems ?? []),
-//     [props.defaultCheckedItems],
-//   );
-//   const [checkedSelection, checkedSelectionManager] = useSelection<TreeItemValue>({
-//     selectionMode: props.selectionMode ?? 'single',
-//     selectedItems: selections.checkedSelection,
-//     defaultSelectedItems: defaultSelections.checkedSelection,
-//   });
-//   const [mixedSelection, setMixedSelection] = useControllableState({
-//     initialState: ImmutableSet.empty,
-//     defaultState: React.useMemo(
-//       () => ImmutableSet.create(defaultSelections.mixedSelection),
-//       [defaultSelections.mixedSelection],
-//     ),
-//     state: React.useMemo(() => ImmutableSet.create(selections.mixedSelection), [selections.mixedSelection]),
-//   });
-
-//   const updateCheckedItems = useEventCallback((data: TreeCheckedChangeData) => {
-//     if (props.selectionMode === 'single') {
-//       checkedSelectionManager.selectItem(data.value);
-//       return;
-//     }
-//     if (walkerRef.current === null) {
-//       return;
-//     }
-//     const nextSelectedState = !checkedSelectionManager.isSelected(data.value);
-
-//     let treeItemValues = getAllSubTreeItemValues(data).add(data.value);
-
-//     let mixedValues: ImmutableSet<TreeItemValue> = ImmutableSet.empty;
-
-//     walkerRef.current.currentElement = data.event.currentTarget;
-//     while (walkerRef.current.parentElement() !== null) {
-//       const descendants = Array.from(
-//         walkerRef.current.currentElement.querySelectorAll<HTMLElement>('[role="treeitem"]'),
-//       ).filter(item => item.getAttribute(dataTreeItemValueAttrName) !== data.value);
-//       const isAllSiblingsEqualSelectionState = descendants.every(item => {
-//         return (
-//           (item.getAttribute('aria-selected') === 'true') === nextSelectedState ||
-//           treeItemValues.has(item.getAttribute(dataTreeItemValueAttrName) as TreeItemValue)
-//         );
-//       });
-//       if (isAllSiblingsEqualSelectionState) {
-//         treeItemValues = treeItemValues.add(
-//           walkerRef.current.currentElement.getAttribute(dataTreeItemValueAttrName) as TreeItemValue,
-//         );
-//         mixedValues = mixedValues.delete(
-//           walkerRef.current.currentElement.getAttribute(dataTreeItemValueAttrName) as TreeItemValue,
-//         );
-//       } else {
-//         treeItemValues = treeItemValues
-//           .delete(walkerRef.current.currentElement.getAttribute(dataTreeItemValueAttrName) as TreeItemValue)
-//           .add(data.value);
-//         mixedValues = mixedValues.add(
-//           walkerRef.current.currentElement.getAttribute(dataTreeItemValueAttrName) as TreeItemValue,
-//         );
-//       }
-//     }
-//     unstable_batchedUpdates(() => {
-//       nextSelectedState
-//         ? checkedSelectionManager.selectItems(treeItemValues)
-//         : checkedSelectionManager.deselectItems(treeItemValues);
-//       let nextMixedSelection = ImmutableSet.create(mixedSelection);
-//       for (const value of mixedValues) {
-//         nextMixedSelection = nextMixedSelection.add(value);
-//       }
-//       for (const value of treeItemValues) {
-//         nextMixedSelection = nextMixedSelection.delete(value);
-//       }
-//       setMixedSelection(nextMixedSelection);
-//     });
-//   });
-//   return [checkedSelection, mixedSelection, updateCheckedItems, rootRef] as const;
-// }
-
-// function getAllSubTreeItemValues(data: TreeCheckedChangeData) {
-//   const subTreeItems = Array.from(data.event.currentTarget.querySelectorAll('[role="treeitem"]'));
-//   const values = new Set<TreeItemValue>();
-//   for (const item of subTreeItems) {
-//     values.add(item.getAttribute(dataTreeItemValueAttrName) as TreeItemValue);
-//   }
-//   return ImmutableSet.dangerouslyCreate(values);
-// }
diff --git a/packages/react-components/react-tree/src/components/Tree/useNestedControllableCheckedItems.ts b/packages/react-components/react-tree/src/components/Tree/useNestedControllableCheckedItems.ts
new file mode 100644
index 00000000000000..9c1a2c646f368c
--- /dev/null
+++ b/packages/react-components/react-tree/src/components/Tree/useNestedControllableCheckedItems.ts
@@ -0,0 +1,22 @@
+import * as React from 'react';
+import type { TreeCheckedChangeData, TreeProps } from './Tree.types';
+import { ImmutableMap } from '../../utils/ImmutableMap';
+import { createCheckedItems } from '../../utils/createCheckedItems';
+import { TreeItemValue } from '../TreeItem/TreeItem.types';
+
+export function useNestedCheckedItems(props: Pick<TreeProps, 'checkedItems'>) {
+  return React.useMemo(() => createCheckedItems(props.checkedItems), [props.checkedItems]);
+}
+
+export function createNextNestedCheckedItems(
+  data: TreeCheckedChangeData,
+  previousCheckedItems: ImmutableMap<TreeItemValue, 'mixed' | boolean>,
+): ImmutableMap<TreeItemValue, 'mixed' | boolean> {
+  if (data.selectionMode === 'single') {
+    return ImmutableMap.create([[data.value, data.checked]]);
+  }
+  if (data.selectionMode === 'multiselect') {
+    return previousCheckedItems.set(data.value, data.checked);
+  }
+  return previousCheckedItems;
+}
diff --git a/packages/react-components/react-tree/src/components/Tree/useTree.ts b/packages/react-components/react-tree/src/components/Tree/useTree.ts
index 6c9906331e7e90..06fc907d411274 100644
--- a/packages/react-components/react-tree/src/components/Tree/useTree.ts
+++ b/packages/react-components/react-tree/src/components/Tree/useTree.ts
@@ -11,17 +11,25 @@ import type {
   TreeState,
 } from './Tree.types';
 import { createNextOpenItems, useControllableOpenItems } from '../../hooks/useControllableOpenItems';
-import { useTreeNavigation } from './useTreeNavigation';
-import { useControllableCheckedItems } from './useControllableCheckedItems';
+import { createNextNestedCheckedItems, useNestedCheckedItems } from './useNestedControllableCheckedItems';
 import { useTreeContext_unstable } from '../../contexts/treeContext';
 import { useRootTree } from '../../hooks/useRootTree';
 import { useSubtree } from '../../hooks/useSubtree';
 import { HTMLElementWalker, createHTMLElementWalker } from '../../utils/createHTMLElementWalker';
 import { treeItemFilter } from '../../utils/treeItemFilter';
+import { useTreeNavigation } from './useTreeNavigation';
 
 export const useTree_unstable = (props: TreeProps, ref: React.Ref<HTMLElement>): TreeState => {
+  const isSubtree = useTreeContext_unstable(ctx => ctx.level > 0);
+  // as isSubTree is static, this doesn't break rule of hooks
+  // and if this becomes an issue later on, this can be easily converted
+  // eslint-disable-next-line react-hooks/rules-of-hooks
+  return isSubtree ? useSubtree(props, ref) : useNestedRootTree(props, ref);
+};
+
+function useNestedRootTree(props: TreeProps, ref: React.Ref<HTMLElement>): TreeState {
   const [openItems, setOpenItems] = useControllableOpenItems(props);
-  const [checkedItems] = useControllableCheckedItems(props);
+  const checkedItems = useNestedCheckedItems(props);
   const { navigate, initialize } = useTreeNavigation();
   const walkerRef = React.useRef<HTMLElementWalker>();
   const initializeWalker = React.useCallback(
@@ -35,12 +43,22 @@ export const useTree_unstable = (props: TreeProps, ref: React.Ref<HTMLElement>):
   );
 
   const handleOpenChange = useEventCallback((event: TreeOpenChangeEvent, data: TreeOpenChangeData) => {
-    props.onOpenChange?.(event, data);
-    setOpenItems(createNextOpenItems(data, openItems));
+    const nextOpenItems = createNextOpenItems(data, openItems);
+    props.onOpenChange?.(event, {
+      ...data,
+      openItems: nextOpenItems.dangerouslyGetInternalSet_unstable(),
+    });
+    setOpenItems(nextOpenItems);
   });
+
   const handleCheckedChange = useEventCallback((event: TreeCheckedChangeEvent, data: TreeCheckedChangeData) => {
-    props.onCheckedChange?.(event, data);
-    // TODO: implement next checked items for  tree
+    if (walkerRef.current) {
+      const nextCheckedItems = createNextNestedCheckedItems(data, checkedItems);
+      props.onCheckedChange?.(event, {
+        ...data,
+        checkedItems: nextCheckedItems.dangerouslyGetInternalMap_unstable(),
+      });
+    }
   });
   const handleNavigation = useEventCallback(
     (event: TreeNavigationEvent_unstable, data: TreeNavigationData_unstable) => {
@@ -51,21 +69,16 @@ export const useTree_unstable = (props: TreeProps, ref: React.Ref<HTMLElement>):
     },
   );
 
-  const baseProps = {
-    ...props,
-    openItems,
-    checkedItems,
-    onOpenChange: handleOpenChange,
-    // eslint-disable-next-line @typescript-eslint/naming-convention
-    onNavigation_unstable: handleNavigation,
-    onCheckedChange: handleCheckedChange,
-  };
-
-  const baseRef = useMergedRefs(ref, initializeWalker);
-
-  const isSubtree = useTreeContext_unstable(ctx => ctx.level > 0);
-  // as isSubTree is static, this doesn't break rule of hooks
-  // and if this becomes an issue later on, this can be easily converted
-  // eslint-disable-next-line react-hooks/rules-of-hooks
-  return isSubtree ? useSubtree(baseProps, baseRef) : useRootTree(baseProps, baseRef);
-};
+  return useRootTree(
+    {
+      ...props,
+      openItems,
+      checkedItems,
+      onOpenChange: handleOpenChange,
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      onNavigation_unstable: handleNavigation,
+      onCheckedChange: handleCheckedChange,
+    },
+    useMergedRefs(ref, initializeWalker),
+  );
+}
diff --git a/packages/react-components/react-tree/src/components/TreeItem/useTreeItem.tsx b/packages/react-components/react-tree/src/components/TreeItem/useTreeItem.tsx
index af3b56d89a7140..d15434395c592c 100644
--- a/packages/react-components/react-tree/src/components/TreeItem/useTreeItem.tsx
+++ b/packages/react-components/react-tree/src/components/TreeItem/useTreeItem.tsx
@@ -3,7 +3,7 @@ import { getNativeElementProps, useId, useMergedRefs } from '@fluentui/react-uti
 import { useEventCallback } from '@fluentui/react-utilities';
 import { elementContains } from '@fluentui/react-portal';
 import type { TreeItemProps, TreeItemState } from './TreeItem.types';
-import { useTreeContext_unstable, useTreeItemContext_unstable } from '../../contexts/index';
+import { useTreeContext_unstable } from '../../contexts/index';
 import { dataTreeItemValueAttrName } from '../../utils/getTreeItemValueFromElement';
 import { Space } from '@fluentui/keyboard-keys';
 import { treeDataTypes } from '../../utils/tokens';
@@ -43,13 +43,7 @@ export function useTreeItem_unstable(props: TreeItemProps, ref: React.Ref<HTMLDi
 
   const open = useTreeContext_unstable(ctx => ctx.openItems.has(value));
   const selectionMode = useTreeContext_unstable(ctx => ctx.selectionMode);
-  const parentChecked = useTreeItemContext_unstable(ctx => ctx.checked);
-  const checked = useTreeContext_unstable(ctx => {
-    if (selectionMode === 'multiselect' && typeof parentChecked === 'boolean') {
-      return parentChecked;
-    }
-    return ctx.checkedItems.get(value);
-  });
+  const checked = useTreeContext_unstable(ctx => ctx.checkedItems.get(value) ?? false);
 
   const handleClick = useEventCallback((event: React.MouseEvent<HTMLDivElement>) => {
     onClick?.(event);
diff --git a/packages/react-components/react-tree/src/components/TreeItemLayout/TreeItemLayout.test.tsx b/packages/react-components/react-tree/src/components/TreeItemLayout/TreeItemLayout.test.tsx
index 6aaf890606d6bb..149f8c27284abf 100644
--- a/packages/react-components/react-tree/src/components/TreeItemLayout/TreeItemLayout.test.tsx
+++ b/packages/react-components/react-tree/src/components/TreeItemLayout/TreeItemLayout.test.tsx
@@ -17,6 +17,7 @@ const Wrapper: React.FC = ({ children }) => (
       isAsideVisible: true,
       itemType: 'leaf',
       open: false,
+      checked: false,
     }}
   >
     {children}
diff --git a/packages/react-components/react-tree/src/components/TreeItemLayout/useTreeItemLayout.tsx b/packages/react-components/react-tree/src/components/TreeItemLayout/useTreeItemLayout.tsx
index 6c81bdc5165a0f..8877afccce6e16 100644
--- a/packages/react-components/react-tree/src/components/TreeItemLayout/useTreeItemLayout.tsx
+++ b/packages/react-components/react-tree/src/components/TreeItemLayout/useTreeItemLayout.tsx
@@ -35,7 +35,7 @@ export const useTreeItemLayout_unstable = (
   const selectionRef = useTreeItemContext_unstable(ctx => ctx.selectionRef);
   const expandIconRef = useTreeItemContext_unstable(ctx => ctx.expandIconRef);
   const actionsRef = useTreeItemContext_unstable(ctx => ctx.actionsRef);
-  const checked = useTreeItemContext_unstable(ctx => ctx.checked ?? false);
+  const checked = useTreeItemContext_unstable(ctx => ctx.checked);
   const isBranch = useTreeItemContext_unstable(ctx => ctx.itemType === 'branch');
 
   const expandIcon = resolveShorthand(props.expandIcon, {
diff --git a/packages/react-components/react-tree/src/components/TreeItemPersonaLayout/TreeItemPersonaLayout.test.tsx b/packages/react-components/react-tree/src/components/TreeItemPersonaLayout/TreeItemPersonaLayout.test.tsx
index 43cfb06e103a15..6c88f97e16281a 100644
--- a/packages/react-components/react-tree/src/components/TreeItemPersonaLayout/TreeItemPersonaLayout.test.tsx
+++ b/packages/react-components/react-tree/src/components/TreeItemPersonaLayout/TreeItemPersonaLayout.test.tsx
@@ -17,6 +17,7 @@ const Wrapper: React.FC = ({ children }) => (
       isAsideVisible: true,
       itemType: 'leaf',
       open: false,
+      checked: false,
     }}
   >
     {children}
diff --git a/packages/react-components/react-tree/src/contexts/treeItemContext.ts b/packages/react-components/react-tree/src/contexts/treeItemContext.ts
index 8dc467e07980ca..58526e81a1f717 100644
--- a/packages/react-components/react-tree/src/contexts/treeItemContext.ts
+++ b/packages/react-components/react-tree/src/contexts/treeItemContext.ts
@@ -15,7 +15,7 @@ export type TreeItemContextValue = {
   itemType: TreeItemType;
   value: TreeItemValue;
   open: boolean;
-  checked?: TreeSelectionValue;
+  checked: TreeSelectionValue;
 };
 
 const defaultContextValue: TreeItemContextValue = {
@@ -29,7 +29,7 @@ const defaultContextValue: TreeItemContextValue = {
   isAsideVisible: false,
   itemType: 'leaf',
   open: false,
-  checked: undefined,
+  checked: false,
 };
 
 export const TreeItemContext: Context<TreeItemContextValue | undefined> = createContext<
diff --git a/packages/react-components/react-tree/src/utils/getTreeItemValueFromElement.ts b/packages/react-components/react-tree/src/utils/getTreeItemValueFromElement.ts
index d5ead44bb79632..08871d0b13d1af 100644
--- a/packages/react-components/react-tree/src/utils/getTreeItemValueFromElement.ts
+++ b/packages/react-components/react-tree/src/utils/getTreeItemValueFromElement.ts
@@ -1,5 +1,7 @@
+import type { TreeItemValue } from '../TreeItem';
+
 export const dataTreeItemValueAttrName = 'data-fui-tree-item-value';
 
 export const getTreeItemValueFromElement = (element: HTMLElement) => {
-  return element.getAttribute(dataTreeItemValueAttrName);
+  return element.getAttribute(dataTreeItemValueAttrName) as TreeItemValue | null;
 };