diff --git a/common/changes/office-ui-fabric-react/messagebar-aria_2018-03-02-23-40.json b/common/changes/office-ui-fabric-react/messagebar-aria_2018-03-02-23-40.json
new file mode 100644
index 00000000000000..6f017251628879
--- /dev/null
+++ b/common/changes/office-ui-fabric-react/messagebar-aria_2018-03-02-23-40.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "office-ui-fabric-react",
+      "comment": "MessageBar: Aria label for truncated text overflow button and added aria labels for buttons in examples.",
+      "type": "minor"
+    }
+  ],
+  "packageName": "office-ui-fabric-react",
+  "email": "lynam.emily@gmail.com"
+}
\ No newline at end of file
diff --git a/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.tsx b/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.tsx
index b87480c68fd7fd..ee806b0537517f 100644
--- a/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.tsx
+++ b/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.tsx
@@ -114,7 +114,7 @@ export class MessageBar extends BaseComponent<IMessageBarProps, IMessageBarState
             className={ css('ms-MessageBar-expand', styles.expand) }
             onClick={ this._onClick }
             iconProps={ { iconName: this.state.expandSingleLine ? 'DoubleChevronUp' : 'DoubleChevronDown' } }
-            ariaLabel={ this.props.dismissButtonAriaLabel }
+            ariaLabel={ this.props.overflowButtonAriaLabel }
           />
         </div>
       );
diff --git a/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.types.ts b/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.types.ts
index 3fb450e9eeed32..43922025a38222 100644
--- a/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.types.ts
+++ b/packages/office-ui-fabric-react/src/components/MessageBar/MessageBar.types.ts
@@ -54,6 +54,11 @@ export interface IMessageBarProps extends React.HTMLAttributes<HTMLElement> {
   * @defaultvalue false
   */
   truncated?: boolean;
+
+  /**
+  * Aria label on overflow button if truncated is defined.
+  */
+  overflowButtonAriaLabel?: string;
 }
 
 export enum MessageBarType {
diff --git a/packages/office-ui-fabric-react/src/components/MessageBar/examples/MessageBar.Basic.Example.tsx b/packages/office-ui-fabric-react/src/components/MessageBar/examples/MessageBar.Basic.Example.tsx
index 1082a2ad735240..e484f8ac25c881 100644
--- a/packages/office-ui-fabric-react/src/components/MessageBar/examples/MessageBar.Basic.Example.tsx
+++ b/packages/office-ui-fabric-react/src/components/MessageBar/examples/MessageBar.Basic.Example.tsx
@@ -20,6 +20,7 @@ export const MessageBarBasicExample = () => (
       messageBarType={ MessageBarType.error }
       isMultiline={ false }
       onDismiss={ log('test') }
+      dismissButtonAriaLabel='Close'
     >
       Error lorem ipsum dolor sit amet, a elit sem interdum consectetur adipiscing elit. <Link href='www.bing.com'>Visit our website.</Link>
     </MessageBar>
@@ -29,7 +30,9 @@ export const MessageBarBasicExample = () => (
       messageBarType={ MessageBarType.blocked }
       isMultiline={ false }
       onDismiss={ log('test') }
+      dismissButtonAriaLabel='Close'
       truncated={ true }
+      overflowButtonAriaLabel='Overflow'
     >
       Blocked lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi luctus, purus a lobortis tristique, odio augue pharetra metus, ac placerat nunc mi nec dui. Vestibulum aliquam et nunc semper scelerisque. Curabitur vitae orci nec quam condimentum porttitor et sed lacus. Vivamus ac efficitur leo. Cras faucibus mauris libero, ac placerat erat euismod et. Donec pulvinar commodo odio sit amet faucibus. In hac habitasse platea dictumst. Duis eu ante commodo, condimentum nibh pellentesque, laoreet enim. Fusce massa lorem, ultrices eu mi a, fermentum suscipit magna. Integer porta purus pulvinar, hendrerit felis eget, condimentum mauris. <Link href='www.bing.com'>Visit our website.</Link>
     </MessageBar>
@@ -65,6 +68,7 @@ export const MessageBarBasicExample = () => (
     <Label>Warning MessageBar - defaults to multiline, with dismiss and action buttons</Label>
     <MessageBar
       onDismiss={ log('test') }
+      dismissButtonAriaLabel='Close'
       messageBarType={ MessageBarType.warning }
       ariaLabel='Aria help text here'
       actions={