diff --git a/ReactAndroid/src/main/java/com/facebook/react/ReactActivity.java b/ReactAndroid/src/main/java/com/facebook/react/ReactActivity.java
index d708e7dc2..b6bdfb0b5 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/ReactActivity.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/ReactActivity.java
@@ -27,6 +27,7 @@ public abstract class ReactActivity extends Activity implements DefaultHardwareB
       "Overlay permissions needs to be granted in order for react native apps to run in dev mode";
 
   private @Nullable ReactInstanceManager mReactInstanceManager;
+  private @Nullable ReactRootView mReactRootView;
   private LifecycleState mLifecycleState = LifecycleState.BEFORE_RESUME;
   private boolean mDoRefresh = false;
 
@@ -138,7 +139,7 @@ public abstract class ReactActivity extends Activity implements DefaultHardwareB
     }
 
     mReactInstanceManager = createReactInstanceManager();
-    ReactRootView mReactRootView = createRootView();
+    mReactRootView = createRootView();
     mReactRootView.startReactApplication(mReactInstanceManager, getMainComponentName(), getLaunchOptions());
     setContentView(mReactRootView);
   }
@@ -169,6 +170,9 @@ public abstract class ReactActivity extends Activity implements DefaultHardwareB
   protected void onDestroy() {
     super.onDestroy();
 
+    mReactRootView.unmountReactApplication();
+    mReactRootView = null;
+
     if (mReactInstanceManager != null) {
       mReactInstanceManager.destroy();
     }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java b/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
index 2c4802e24..50f7f4077 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
@@ -165,13 +165,18 @@ public class ReactRootView extends SizeMonitoringFrameLayout implements RootView
     // No-op since UIManagerModule handles actually laying out children.
   }
 
+  @Override
+  protected void onAttachedToWindow() {
+    super.onAttachedToWindow();
+    if (mIsAttachedToInstance) {
+      getViewTreeObserver().addOnGlobalLayoutListener(getKeyboardListener());
+    }
+  }
+
   @Override
   protected void onDetachedFromWindow() {
     super.onDetachedFromWindow();
-
-    if (mReactInstanceManager != null && mIsAttachedToInstance) {
-      mReactInstanceManager.detachRootView(this);
-      mIsAttachedToInstance = false;
+    if (mIsAttachedToInstance) {
       getViewTreeObserver().removeOnGlobalLayoutListener(getKeyboardListener());
     }
   }
@@ -217,6 +222,19 @@ public class ReactRootView extends SizeMonitoringFrameLayout implements RootView
     }
   }
 
+  /**
+   * Unmount the react application at this root view, reclaiming any JS memory associated with that
+   * application. If {@link #startReactApplication} is called, this method must be called before the
+   * ReactRootView is garbage collected (typically in your Activity's onDestroy, or in your Fragment's
+   * onDestroyView).
+   */
+  public void unmountReactApplication() {
+    if (mReactInstanceManager != null && mIsAttachedToInstance) {
+      mReactInstanceManager.detachRootView(this);
+      mIsAttachedToInstance = false;
+    }
+  }
+
   /* package */ String getJSModuleName() {
     return Assertions.assertNotNull(mJSModuleName);
   }
@@ -252,6 +270,17 @@ public class ReactRootView extends SizeMonitoringFrameLayout implements RootView
     getViewTreeObserver().addOnGlobalLayoutListener(getKeyboardListener());
   }
 
+  @Override
+  protected void finalize() throws Throwable {
+    super.finalize();
+    Assertions.assertCondition(
+      !mIsAttachedToInstance,
+      "The application this ReactRootView was rendering was not unmounted before the ReactRootView " +
+        "was garbage collected. This usually means that your application is leaking large amounts of " +
+        "memory. To solve this, make sure to call ReactRootView#unmountReactApplication in the onDestroy() " +
+        "of your hosting Activity or in the onDestroyView() of your hosting Fragment.");
+  }
+
   private class KeyboardListener implements ViewTreeObserver.OnGlobalLayoutListener {
     private final Rect mVisibleViewArea;
     private final int mMinKeyboardHeightDetected;