diff --git a/src/renderers/native/NativeMethodsMixin.js b/src/renderers/native/NativeMethodsMixin.js
index 0d06e11fef..9b78ed1f9d 100644
--- a/src/renderers/native/NativeMethodsMixin.js
+++ b/src/renderers/native/NativeMethodsMixin.js
@@ -207,7 +207,10 @@ if (__DEV__) {
  * In the future, we should cleanup callbacks by cancelling them instead of
  * using this.
  */
-var mountSafeCallback = function(context: ReactComponent, callback: ?Function): any {
+function mountSafeCallback(
+  context: ReactComponent<any, any, any>,
+  callback: ?Function
+): any {
   return function() {
     if (!callback || (context.isMounted && !context.isMounted())) {
       return undefined;
diff --git a/src/renderers/native/ReactNative.js b/src/renderers/native/ReactNative.js
index e40c6b7576..0305ff2447 100644
--- a/src/renderers/native/ReactNative.js
+++ b/src/renderers/native/ReactNative.js
@@ -28,7 +28,7 @@ var render = function(
   element: ReactElement,
   mountInto: number,
   callback?: ?(() => void)
-): ?ReactComponent {
+): ?ReactComponent<any, any, any> {
   return ReactNativeMount.renderComponent(element, mountInto, callback);
 };
 
diff --git a/src/renderers/native/ReactNativeMount.js b/src/renderers/native/ReactNativeMount.js
index 0694ec262c..8fc575d97f 100644
--- a/src/renderers/native/ReactNativeMount.js
+++ b/src/renderers/native/ReactNativeMount.js
@@ -101,7 +101,7 @@ var ReactNativeMount = {
     nextElement: ReactElement,
     containerTag: number,
     callback?: ?(() => void)
-  ): ?ReactComponent {
+  ): ?ReactComponent<any, any, any> {
     var nextWrappedElement = new ReactElement(
       TopLevelWrapper,
       null,
@@ -237,7 +237,7 @@ var ReactNativeMount = {
    * @see {ReactNativeMount.unmountComponentAtNode}
    */
   unmountComponentFromNode: function(
-    instance: ReactComponent,
+    instance: ReactComponent<any, any, any>,
     containerID: number
   ) {
     // Call back into native to remove all of the subviews from this container
diff --git a/src/renderers/native/createReactNativeComponentClass.js b/src/renderers/native/createReactNativeComponentClass.js
index 123e42fa78..adb0740bcf 100644
--- a/src/renderers/native/createReactNativeComponentClass.js
+++ b/src/renderers/native/createReactNativeComponentClass.js
@@ -42,7 +42,7 @@ var createReactNativeComponentClass = function(
   Constructor.prototype = new ReactNativeBaseComponent(viewConfig);
   Constructor.prototype.constructor = Constructor;
 
-  return ((Constructor: any): ReactClass);
+  return ((Constructor: any): ReactClass<any>);
 };
 
 module.exports = createReactNativeComponentClass;
diff --git a/src/renderers/noop/ReactNoop.js b/src/renderers/noop/ReactNoop.js
index b1d63ec9d3..1b411a2f3f 100644
--- a/src/renderers/noop/ReactNoop.js
+++ b/src/renderers/noop/ReactNoop.js
@@ -40,7 +40,7 @@ var NoopRenderer = ReactFiberReconciler({
 
 var ReactNoop = {
 
-  render(element : ReactElement) {
+  render(element : ReactElement<any>) {
 
     NoopRenderer.mountNewRoot(element);
 
diff --git a/src/renderers/shared/fiber/ReactChildFiber.js b/src/renderers/shared/fiber/ReactChildFiber.js
index bbb666cab0..5461d40515 100644
--- a/src/renderers/shared/fiber/ReactChildFiber.js
+++ b/src/renderers/shared/fiber/ReactChildFiber.js
@@ -35,7 +35,7 @@ function createSubsequentChild(parent : Fiber, previousSibling : Fiber, newChild
 
   switch (newChildren.$$typeof) {
     case REACT_ELEMENT_TYPE: {
-      const element = (newChildren : ReactElement);
+      const element = (newChildren : ReactElement<any>);
       const child = ReactFiber.createFiberFromElement(element);
       previousSibling.sibling = child;
       child.parent = parent;
@@ -80,7 +80,7 @@ function createFirstChild(parent, newChildren) {
 
   switch (newChildren.$$typeof) {
     case REACT_ELEMENT_TYPE: {
-      const element = (newChildren : ReactElement);
+      const element = (newChildren : ReactElement<any>);
       const child = ReactFiber.createFiberFromElement(element);
       child.parent = parent;
       return child;
diff --git a/src/renderers/shared/fiber/ReactFiberReconciler.js b/src/renderers/shared/fiber/ReactFiberReconciler.js
index 4a13a6531b..c590e35f3e 100644
--- a/src/renderers/shared/fiber/ReactFiberReconciler.js
+++ b/src/renderers/shared/fiber/ReactFiberReconciler.js
@@ -39,7 +39,7 @@ export type HostConfig<T, P, I> = {
 type OpaqueID = {};
 
 export type Reconciler = {
-  mountNewRoot(element : ReactElement) : OpaqueID;
+  mountNewRoot(element : ReactElement<any>) : OpaqueID;
 };
 
 module.exports = function<T, P, I>(config : HostConfig<T, P, I>) : Reconciler {
@@ -109,7 +109,7 @@ module.exports = function<T, P, I>(config : HostConfig<T, P, I>) : Reconciler {
 
   return {
 
-    mountNewRoot(element : ReactElement) : OpaqueID {
+    mountNewRoot(element : ReactElement<any>) : OpaqueID {
 
       ensureLowPriIsScheduled();
 
diff --git a/src/renderers/shared/fiber/isomorphic/ReactTypes.js b/src/renderers/shared/fiber/isomorphic/ReactTypes.js
index 4c8c69571c..643048b469 100644
--- a/src/renderers/shared/fiber/isomorphic/ReactTypes.js
+++ b/src/renderers/shared/fiber/isomorphic/ReactTypes.js
@@ -14,7 +14,7 @@
 
 import type { ReactCoroutine, ReactYield } from 'ReactCoroutine';
 
-export type ReactNode = ReactElement | ReactCoroutine | ReactYield | ReactText | ReactFragment;
+export type ReactNode = ReactElement<any> | ReactCoroutine | ReactYield | ReactText | ReactFragment;
 
 export type ReactFragment = ReactEmpty | Iterable<ReactNode>;
 
diff --git a/src/renderers/testing/ReactTestMount.js b/src/renderers/testing/ReactTestMount.js
index 517d1c0839..45e6cfd290 100644
--- a/src/renderers/testing/ReactTestMount.js
+++ b/src/renderers/testing/ReactTestMount.js
@@ -96,7 +96,7 @@ var ReactHostMount = {
 
   render: function(
     nextElement: ReactElement
-  ): ?ReactComponent {
+  ): ?ReactElement<any, any, any> {
     var nextWrappedElement = new ReactElement(
       TopLevelWrapper,
       null,