diff --git a/change/@fluentui-react-portal-cc923a38-5b66-41a7-95fb-306fefd5e3f4.json b/change/@fluentui-react-portal-cc923a38-5b66-41a7-95fb-306fefd5e3f4.json
new file mode 100644
index 0000000000000..d33d08585afeb
--- /dev/null
+++ b/change/@fluentui-react-portal-cc923a38-5b66-41a7-95fb-306fefd5e3f4.json
@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "clean up parent reference to avoid memory leaks",
+  "packageName": "@fluentui/react-portal",
+  "email": "arthurd@microsoft.com",
+  "dependentChangeType": "patch"
+}
diff --git a/packages/react-components/react-portal/src/components/Portal/usePortal.ts b/packages/react-components/react-portal/src/components/Portal/usePortal.ts
index 66d748f5f6c23..dc69fccc93d03 100644
--- a/packages/react-components/react-portal/src/components/Portal/usePortal.ts
+++ b/packages/react-components/react-portal/src/components/Portal/usePortal.ts
@@ -26,6 +26,9 @@ export const usePortal_unstable = (props: PortalProps): PortalState => {
     if (state.virtualParentRootRef.current && state.mountNode) {
       setVirtualParent(state.mountNode, state.virtualParentRootRef.current);
     }
+    return () => {
+      if (state.mountNode) {setVirtualParent(state.mountNode, undefined);}
+    };
   }, [state.virtualParentRootRef, state.mountNode]);
 
   return state;