diff --git a/common/changes/office-ui-fabric-react/users-adtran-overflowMenuProps-cmdbar_2018-05-08-21-16.json b/common/changes/office-ui-fabric-react/users-adtran-overflowMenuProps-cmdbar_2018-05-08-21-16.json
new file mode 100644
index 00000000000000..76588362200034
--- /dev/null
+++ b/common/changes/office-ui-fabric-react/users-adtran-overflowMenuProps-cmdbar_2018-05-08-21-16.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "office-ui-fabric-react",
+      "comment": "Added overflowMenuProps property to CommandBar",
+      "type": "minor"
+    }
+  ],
+  "packageName": "office-ui-fabric-react",
+  "email": "adtran@microsoft.com"
+}
\ No newline at end of file
diff --git a/packages/office-ui-fabric-react/src/components/Button/BaseButton.tsx b/packages/office-ui-fabric-react/src/components/Button/BaseButton.tsx
index 895d5194fa414c..310a4bc0076e0f 100644
--- a/packages/office-ui-fabric-react/src/components/Button/BaseButton.tsx
+++ b/packages/office-ui-fabric-react/src/components/Button/BaseButton.tsx
@@ -8,7 +8,8 @@ import {
   getId,
   getNativeProps,
   KeyCodes,
-  createRef
+  createRef,
+  css
 } from '../../Utilities';
 import { Icon } from '../../Icon';
 import { DirectionalHint } from '../../common/DirectionalHint';
@@ -431,7 +432,7 @@ export class BaseButton extends BaseComponent<IBaseButtonProps, IBaseButtonState
         directionalHint={ DirectionalHint.bottomLeftEdge }
         { ...menuProps }
         shouldFocusOnContainer={ this.state.menuProps ? this.state.menuProps.shouldFocusOnContainer : undefined }
-        className={ 'ms-BaseButton-menuhost ' + menuProps.className }
+        className={ css('ms-BaseButton-menuhost', menuProps.className) }
         target={ this._isSplitButton ? this._splitButtonContainer.current : this._buttonElement.current }
         labelElementId={ this._labelId }
         onDismiss={ onDismiss }
diff --git a/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.tsx b/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.tsx
index 5d23683b041f6b..7a585c22cf448b 100644
--- a/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.tsx
+++ b/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.tsx
@@ -156,7 +156,7 @@ export class CommandBar extends BaseComponent<ICommandBarProps, ICommandBarState
         </FocusZone>
         { (contextualMenuProps) ?
           (<ContextualMenu
-            className={ css('ms-CommandBar-menuHost') }
+            className={ 'ms-CommandBar-menuHost' }
             directionalHint={ DirectionalHint.bottomAutoEdge }
             { ...contextualMenuProps }
             target={ contextualMenuTarget }
@@ -386,7 +386,7 @@ export class CommandBar extends BaseComponent<ICommandBarProps, ICommandBarState
   }
 
   private _updateRenderedItems(): void {
-    const { items, overflowItems } = this.props;
+    const { items, overflowItems, overflowMenuProps } = this.props;
     const commandSurface = this._commandSurface.current;
     const farCommandSurface = this._farCommandSurface.current;
     const commandBarRegion = this._commandBarRegion.current;
@@ -436,8 +436,10 @@ export class CommandBar extends BaseComponent<ICommandBarProps, ICommandBarState
     }
 
     const renderedContextualMenuProps = this._getContextualMenuPropsAfterUpdate(
-      renderedItems.concat(this.state.renderedFarItems!),
-      renderedOverflowItems!);
+        renderedItems.concat(this.state.renderedFarItems!),
+        renderedOverflowItems!,
+        overflowMenuProps!
+      );
 
     this.setState({
       renderedItems: renderedItems,
@@ -477,7 +479,7 @@ export class CommandBar extends BaseComponent<ICommandBarProps, ICommandBarState
       this.setState({
         expandedMenuId: ev.currentTarget.id,
         expandedMenuItemKey: OVERFLOW_KEY,
-        contextualMenuProps: { items: this.state.renderedOverflowItems! },
+        contextualMenuProps: { ...this.props.overflowMenuProps!, items: this.state.renderedOverflowItems! },
         contextualMenuTarget: ev.currentTarget
       });
     }
@@ -490,7 +492,7 @@ export class CommandBar extends BaseComponent<ICommandBarProps, ICommandBarState
       const { contextualMenuProps } = this.state;
 
       if (contextualMenuProps && contextualMenuProps.onDismiss) {
-        this.state.contextualMenuProps!.onDismiss!(ev);
+        contextualMenuProps!.onDismiss!(ev);
       }
 
       this.setState({
@@ -509,16 +511,17 @@ export class CommandBar extends BaseComponent<ICommandBarProps, ICommandBarState
       renderedItems: nextProps.items || [],
       contextualMenuProps: this._getContextualMenuPropsAfterUpdate(
         nextProps.items.concat(nextProps.farItems!),
-        nextProps.overflowItems!)!,
+        nextProps.overflowItems!,
+        nextProps.overflowMenuProps!)!,
       renderedFarItems: nextProps.farItems || undefined
     };
   }
 
-  private _getContextualMenuPropsAfterUpdate(renderedItems: IContextualMenuItem[], overflowItems: IContextualMenuItem[]): IContextualMenuProps | undefined {
+  private _getContextualMenuPropsAfterUpdate(renderedItems: IContextualMenuItem[], overflowItems: IContextualMenuItem[], overflowMenuProps: Partial<IContextualMenuProps>): IContextualMenuProps | undefined {
     if (this.state && this.state.expandedMenuItemKey) {
       if (this.state.expandedMenuItemKey === OVERFLOW_KEY) {
         // Keep the overflow menu open
-        return { items: overflowItems };
+        return { ...overflowMenuProps, items: overflowItems };
       } else {
         // Find the currently open key in the new props
         const matchingItem = renderedItems.filter(item => item.key === this.state.expandedMenuItemKey);
diff --git a/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.types.ts b/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.types.ts
index 216e55194332ce..7aca28a7fcf059 100644
--- a/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.types.ts
+++ b/packages/office-ui-fabric-react/src/components/CommandBar/CommandBar.types.ts
@@ -1,5 +1,5 @@
 import * as React from 'react';
-import { IContextualMenuItem } from '../ContextualMenu/index';
+import { IContextualMenuItem, IContextualMenuProps } from '../ContextualMenu/index';
 
 export interface ICommandBar {
   /**
@@ -36,6 +36,11 @@ export interface ICommandBarProps extends React.HTMLAttributes<HTMLDivElement> {
    */
   overflowItems?: IContextualMenuItem[];
 
+  /**
+  * Menu props to be passed to overflow elipsis
+  */
+  overflowMenuProps?: Partial<IContextualMenuProps>;
+
   /**
    * Text to be read by screen readers if there are overflow items and focus is on elipsis button
    */