diff --git a/packages/react-error-overlay/src/index.js b/packages/react-error-overlay/src/index.js
index a800595cffb..1cccd49d8c3 100644
--- a/packages/react-error-overlay/src/index.js
+++ b/packages/react-error-overlay/src/index.js
@@ -167,3 +167,15 @@ window.__REACT_ERROR_OVERLAY_GLOBAL_HOOK__.iframeReady = function iframeReady()
   isLoadingIframe = false;
   updateIframeContent();
 };
+
+var testFunc = function testFn() {};
+if ((testFunc.name || testFunc.toString()).indexOf('testFn') !== -1) {
+  console.warn(
+    'It looks like you are using `react-error-overlay` in production. When ' +
+      'deploying an application, `react-error-overlay` should be excluded ' +
+      'as it is a heavy dependency meant for development.\n\n' +
+      'Consider adding an error boundary to your tree to customize error ' +
+      'handling behavior. See https://fb.me/react-error-boundaries for more ' +
+      'information.'
+  );
+}