diff --git a/src/renderers/dom/shared/ReactDOMComponent.js b/src/renderers/dom/shared/ReactDOMComponent.js
index f4a95edbe0259..3e789d33b14ac 100644
--- a/src/renderers/dom/shared/ReactDOMComponent.js
+++ b/src/renderers/dom/shared/ReactDOMComponent.js
@@ -187,6 +187,13 @@ function assertValidProps(component, props) {
       'those nodes are unexpectedly modified or duplicated. This is ' +
       'probably not intentional.'
     );
+    warning(
+      props.onFocusIn == null &&
+      props.onFocusOut == null,
+      'React uses onFocus and onBlur instead of onFocusIn and onFocusOut. ' +
+      'All React events are normalized to bubble, so onFocusIn and onFocusOut ' +
+      'are not needed/supported by React.'
+    );
   }
   invariant(
     props.style == null || typeof props.style === 'object',
diff --git a/src/renderers/dom/shared/__tests__/ReactDOMComponent-test.js b/src/renderers/dom/shared/__tests__/ReactDOMComponent-test.js
index 7233f16cc5fc0..2fb18a526323b 100644
--- a/src/renderers/dom/shared/__tests__/ReactDOMComponent-test.js
+++ b/src/renderers/dom/shared/__tests__/ReactDOMComponent-test.js
@@ -1234,5 +1234,17 @@ describe('ReactDOMComponent', function() {
       expect(console.error.argsForCall.length).toBe(1);
       expect(console.error.argsForCall[0][0]).toContain('className');
     });
+
+    it('should warn about props that are no longer supported', function() {
+      spyOn(console, 'error');
+      ReactTestUtils.renderIntoDocument(<div />);
+      expect(console.error.argsForCall.length).toBe(0);
+
+      ReactTestUtils.renderIntoDocument(<div onFocusIn={() => {}} />);
+      expect(console.error.argsForCall.length).toBe(1);
+
+      ReactTestUtils.renderIntoDocument(<div onFocusOut={() => {}} />);
+      expect(console.error.argsForCall.length).toBe(2);
+    });
   });
 });