diff --git a/packages/eui/changelogs/upcoming/8849.md b/packages/eui/changelogs/upcoming/8849.md
new file mode 100644
index 00000000000..522c928d862
--- /dev/null
+++ b/packages/eui/changelogs/upcoming/8849.md
@@ -0,0 +1,3 @@
+- Added `includeSelectorInFocusTrap` prop for `EuiFlyout`
+- Added component defaults for `EuiFlyout` that include `includeSelectorInFocusTrap` and `includeFixedHeadersInFocusTrap`
+
diff --git a/packages/eui/src/components/flyout/__snapshots__/flyout.test.tsx.snap b/packages/eui/src/components/flyout/__snapshots__/flyout.test.tsx.snap
index e0d99120e32..6dec7142e58 100644
--- a/packages/eui/src/components/flyout/__snapshots__/flyout.test.tsx.snap
+++ b/packages/eui/src/components/flyout/__snapshots__/flyout.test.tsx.snap
@@ -1125,7 +1125,7 @@ exports[`EuiFlyout renders extra screen reader instructions when fixed EuiHeader
           >
             You are in a modal dialog. Press Escape or tap/click outside the dialog on the shadowed overlay to close.
              
-            You can still continue tabbing through the page headers in addition to the dialog.
+            You can still continue tabbing through other global page landmarks.
           </p>
           <button
             aria-label="Close this dialog"
diff --git a/packages/eui/src/components/flyout/flyout.test.tsx b/packages/eui/src/components/flyout/flyout.test.tsx
index cb64786c7f3..6c7c261d649 100644
--- a/packages/eui/src/components/flyout/flyout.test.tsx
+++ b/packages/eui/src/components/flyout/flyout.test.tsx
@@ -14,6 +14,7 @@ import { shouldRenderCustomStyles } from '../../test/internal';
 
 import { EuiHeader } from '../header';
 import { EuiFlyout, SIZES, PADDING_SIZES, SIDES } from './flyout';
+import { EuiProvider } from '../provider';
 
 jest.mock('../overlay_mask', () => ({
   EuiOverlayMask: ({ headerZindexLocation, maskRef, ...props }: any) => (
@@ -51,10 +52,7 @@ describe('EuiFlyout', () => {
 
     expect(baseElement).toMatchSnapshot();
     expect(
-      queryByText(
-        'You can still continue tabbing through the page headers in addition to the dialog.',
-        { exact: false }
-      )
+      queryByText('You can still continue tabbing through', { exact: false })
     ).toBeTruthy();
 
     // Should not shard or render instructions when `includeFixedHeadersInFocusTrap={false}
@@ -65,12 +63,30 @@ describe('EuiFlyout', () => {
       </>
     );
     expect(
-      queryByText('You can still continue tabbing through the page headers', {
+      queryByText('You can still continue tabbing through', {
         exact: false,
       })
     ).toBeFalsy();
   });
 
+  it('renders extra screen reader instructions when specified selector exists on the page', () => {
+    const { queryByText } = render(
+      <>
+        <div data-custom-sidebar />
+        <EuiFlyout
+          {...requiredProps}
+          onClose={() => {}}
+          includeSelectorInFocusTrap={'[data-custom-sidebar]'}
+          includeFixedHeadersInFocusTrap={false}
+        />
+      </>
+    );
+
+    expect(
+      queryByText('You can still continue tabbing through', { exact: false })
+    ).toBeTruthy();
+  });
+
   it('allows setting custom aria-describedby attributes', () => {
     const { getByTestSubject } = render(
       <>
@@ -308,4 +324,50 @@ describe('EuiFlyout', () => {
       });
     });
   });
+
+  describe('component defaults', () => {
+    test('includeSelectorInFocusTrap', () => {
+      const { queryByText } = render(
+        <EuiProvider
+          componentDefaults={{
+            EuiFlyout: {
+              includeSelectorInFocusTrap: ['[data-custom-sidebar]'],
+            },
+          }}
+        >
+          <div data-custom-sidebar />
+          <EuiFlyout {...requiredProps} onClose={() => {}} />
+        </EuiProvider>,
+        {
+          wrapper: undefined,
+        }
+      );
+
+      expect(
+        queryByText('You can still continue tabbing through', { exact: false })
+      ).toBeTruthy();
+    });
+
+    test('includeFixedHeadersInFocusTrap', () => {
+      const { queryByText } = render(
+        <EuiProvider
+          componentDefaults={{
+            EuiFlyout: {
+              includeFixedHeadersInFocusTrap: false,
+            },
+          }}
+        >
+          <EuiHeader position="fixed" />
+          <EuiFlyout {...requiredProps} onClose={() => {}} />
+        </EuiProvider>,
+        {
+          wrapper: undefined,
+        }
+      );
+
+      expect(
+        queryByText('You can still continue tabbing through', { exact: false })
+      ).not.toBeTruthy();
+    });
+  });
 });
diff --git a/packages/eui/src/components/flyout/flyout.tsx b/packages/eui/src/components/flyout/flyout.tsx
index c541c4a3757..7d6fbf917a3 100644
--- a/packages/eui/src/components/flyout/flyout.tsx
+++ b/packages/eui/src/components/flyout/flyout.tsx
@@ -48,6 +48,7 @@ import { EuiFlyoutCloseButton } from './_flyout_close_button';
 import { euiFlyoutStyles } from './flyout.styles';
 import { EuiFlyoutChild } from './flyout_child';
 import { EuiFlyoutChildProvider } from './flyout_child_manager';
+import { usePropsWithComponentDefaults } from '../provider/component_defaults';
 
 export const TYPES = ['push', 'overlay'] as const;
 type _EuiFlyoutType = (typeof TYPES)[number];
@@ -162,6 +163,11 @@ interface _EuiFlyoutProps {
    * Set this to `false` if you need to disable this behavior for a specific reason.
    */
   includeFixedHeadersInFocusTrap?: boolean;
+
+  /**
+   * Specify additional css selectors to include in the focus trap.
+   */
+  includeSelectorInFocusTrap?: string[] | string;
 }
 
 const defaultElement = 'div';
@@ -179,7 +185,13 @@ export type EuiFlyoutProps<T extends ElementType = typeof defaultElement> =
 
 export const EuiFlyout = forwardRef(
   <T extends ElementType = typeof defaultElement>(
-    {
+    props: EuiFlyoutProps<T>,
+    ref:
+      | ((instance: ComponentPropsWithRef<T> | null) => void)
+      | MutableRefObject<ComponentPropsWithRef<T> | null>
+      | null
+  ) => {
+    const {
       className,
       children,
       as,
@@ -200,14 +212,11 @@ export const EuiFlyout = forwardRef(
       pushAnimation = false,
       focusTrapProps: _focusTrapProps,
       includeFixedHeadersInFocusTrap = true,
+      includeSelectorInFocusTrap,
       'aria-describedby': _ariaDescribedBy,
       ...rest
-    }: EuiFlyoutProps<T>,
-    ref:
-      | ((instance: ComponentPropsWithRef<T> | null) => void)
-      | MutableRefObject<ComponentPropsWithRef<T> | null>
-      | null
-  ) => {
+    } = usePropsWithComponentDefaults('EuiFlyout', props);
+
     const Element = as || defaultElement;
     const maskRef = useRef<HTMLDivElement>(null);
 
@@ -359,34 +368,51 @@ export const EuiFlyout = forwardRef(
      * (both mousedown and mouseup) the overlay mask.
      */
     const flyoutToggle = useRef<Element | null>(document.activeElement);
-    const [fixedHeaders, setFixedHeaders] = useState<HTMLDivElement[]>([]);
+    const [focusTrapShards, setFocusTrapShards] = useState<HTMLElement[]>([]);
+
+    const focusTrapSelectors = useMemo(() => {
+      let selectors: string[] = [];
+
+      if (includeSelectorInFocusTrap) {
+        selectors = Array.isArray(includeSelectorInFocusTrap)
+          ? includeSelectorInFocusTrap
+          : [includeSelectorInFocusTrap];
+      }
 
-    useEffect(() => {
       if (includeFixedHeadersInFocusTrap) {
-        const fixedHeaderEls = document.querySelectorAll<HTMLDivElement>(
-          '.euiHeader[data-fixed-header]'
+        selectors.push('.euiHeader[data-fixed-header]');
+      }
+
+      return selectors;
+    }, [includeSelectorInFocusTrap, includeFixedHeadersInFocusTrap]);
+
+    useEffect(() => {
+      if (focusTrapSelectors.length > 0) {
+        const shardsEls = focusTrapSelectors.flatMap((selector) =>
+          Array.from(document.querySelectorAll<HTMLElement>(selector))
         );
-        setFixedHeaders(Array.from(fixedHeaderEls));
 
-        // Flyouts that are toggled from fixed headers do not have working
+        setFocusTrapShards(Array.from(shardsEls));
+
+        // Flyouts that are toggled from shards do not have working
         // focus trap autoFocus, so we need to focus the flyout wrapper ourselves
-        fixedHeaderEls.forEach((header) => {
-          if (header.contains(flyoutToggle.current)) {
+        shardsEls.forEach((shard) => {
+          if (shard.contains(flyoutToggle.current)) {
             resizeRef?.focus();
           }
         });
       } else {
-        // Clear existing headers if necessary, e.g. switching to `false`
-        setFixedHeaders((headers) => (headers.length ? [] : headers));
+        // Clear existing shards if necessary, e.g. switching to `false`
+        setFocusTrapShards((shards) => (shards.length ? [] : shards));
       }
-    }, [includeFixedHeadersInFocusTrap, resizeRef]);
+    }, [focusTrapSelectors, resizeRef]);
 
     const focusTrapProps: EuiFlyoutProps['focusTrapProps'] = useMemo(
       () => ({
         ..._focusTrapProps,
-        shards: [...fixedHeaders, ...(_focusTrapProps?.shards || [])],
+        shards: [...focusTrapShards, ...(_focusTrapProps?.shards || [])],
       }),
-      [_focusTrapProps, fixedHeaders]
+      [_focusTrapProps, focusTrapShards]
     );
 
     /*
@@ -411,16 +437,16 @@ export const EuiFlyout = forwardRef(
                 default="You are in a non-modal dialog. To close the dialog, press Escape."
               />
             )}{' '}
-            {fixedHeaders.length > 0 && (
+            {focusTrapShards.length > 0 && (
               <EuiI18n
-                token="euiFlyout.screenReaderFixedHeaders"
-                default="You can still continue tabbing through the page headers in addition to the dialog."
+                token="euiFlyout.screenReaderFocusTrapShards"
+                default="You can still continue tabbing through other global page landmarks."
               />
             )}
           </p>
         </EuiScreenReaderOnly>
       ),
-      [hasOverlayMask, descriptionId, fixedHeaders.length]
+      [hasOverlayMask, descriptionId, focusTrapShards.length]
     );
 
     /*
diff --git a/packages/eui/src/components/provider/component_defaults/component_defaults.tsx b/packages/eui/src/components/provider/component_defaults/component_defaults.tsx
index 8373aeb9b37..85e7a60e1c5 100644
--- a/packages/eui/src/components/provider/component_defaults/component_defaults.tsx
+++ b/packages/eui/src/components/provider/component_defaults/component_defaults.tsx
@@ -17,6 +17,7 @@ import React, {
 import type { EuiPortalProps } from '../../portal';
 import type { EuiFocusTrapProps } from '../../focus_trap';
 import type { EuiTablePaginationProps, EuiTableProps } from '../../table';
+import type { EuiFlyoutProps } from '../../flyout';
 
 export type EuiComponentDefaults = {
   /**
@@ -43,6 +44,15 @@ export type EuiComponentDefaults = {
    * Defaults will be inherited by all `EuiBasicTable`s and `EuiInMemoryTable`s.
    */
   EuiTable?: Pick<EuiTableProps, 'responsiveBreakpoint'>;
+
+  /**
+   * Provide a global configuration for `EuiFlyout`s.
+   * Defaults will be inherited by all `EuiFlyout`s.
+   */
+  EuiFlyout?: Pick<
+    EuiFlyoutProps,
+    'includeSelectorInFocusTrap' | 'includeFixedHeadersInFocusTrap'
+  >;
 };
 
 // Declaring as a static const for reference integrity/reducing rerenders