diff --git a/packages/fiber/src/core/renderer.ts b/packages/fiber/src/core/renderer.ts
index 6103141565..3963e7fcff 100644
--- a/packages/fiber/src/core/renderer.ts
+++ b/packages/fiber/src/core/renderer.ts
@@ -226,13 +226,20 @@ function createRenderer<TCanvas>(_roots: Map<TCanvas, Root>, _getEventPriority?:
 
       // Dispose item whenever the reconciler feels like it
       if (shouldDispose && child.dispose && child.type !== 'Scene') {
-        scheduleCallback(idlePriority, () => {
+        const callback = () => {
           try {
             child.dispose()
           } catch (e) {
             /* ... */
           }
-        })
+        }
+
+        // Schedule async at runtime, flush sync in testing
+        if (typeof IS_REACT_ACT_ENVIRONMENT === 'undefined') {
+          scheduleCallback(idlePriority, callback)
+        } else {
+          callback()
+        }
       }
 
       invalidateInstance(parentInstance)
diff --git a/packages/fiber/tests/core/renderer.test.tsx b/packages/fiber/tests/core/renderer.test.tsx
index f970670a38..df07318fb5 100644
--- a/packages/fiber/tests/core/renderer.test.tsx
+++ b/packages/fiber/tests/core/renderer.test.tsx
@@ -963,8 +963,7 @@ describe('renderer', () => {
     expect(ref.current!.userData.attach).toBe(attachedChild.current)
   })
 
-  // TODO: scheduler isn't flushed during testing which prevents disposal
-  it.skip('should not recursively dispose of attached primitives', async () => {
+  it('should not recursively dispose of attached primitives', async () => {
     const meshDispose = jest.fn()
     const primitiveDispose = jest.fn()