diff --git a/packages/events/EventPluginRegistry.js b/packages/events/EventPluginRegistry.js
index ccfaa872dc..efebd984e8 100644
--- a/packages/events/EventPluginRegistry.js
+++ b/packages/events/EventPluginRegistry.js
@@ -15,13 +15,10 @@ import type {
 } from './PluginModuleType';
 
 import invariant from 'fbjs/lib/invariant';
-import lowPriorityWarning from 'shared/lowPriorityWarning';
 
 type NamesToPlugins = {[key: PluginName]: PluginModule<AnyNativeEvent>};
 type EventPluginOrder = null | Array<PluginName>;
 
-let shouldWarnOnInjection = false;
-
 /**
  * Injectable ordering of event plugins.
  */
@@ -32,10 +29,6 @@ let eventPluginOrder: EventPluginOrder = null;
  */
 const namesToPlugins: NamesToPlugins = {};
 
-export function enableWarningOnInjection() {
-  shouldWarnOnInjection = true;
-}
-
 /**
  * Recomputes the plugin list using the injected plugins and plugin ordering.
  *
@@ -228,21 +221,6 @@ export function injectEventPluginOrder(
 export function injectEventPluginsByName(
   injectedNamesToPlugins: NamesToPlugins,
 ): void {
-  if (__DEV__) {
-    if (shouldWarnOnInjection) {
-      const names = Object.keys(injectedNamesToPlugins).join(', ');
-      lowPriorityWarning(
-        false,
-        'Injecting custom event plugins (%s) is deprecated ' +
-          'and will not work in React 17+. Please update your code ' +
-          'to not depend on React internals. The stack trace for this ' +
-          'warning should reveal the library that is using them. ' +
-          'See https://github.com/facebook/react/issues/11689 for a discussion.',
-        names,
-      );
-    }
-  }
-
   let isOrderingDirty = false;
   for (const pluginName in injectedNamesToPlugins) {
     if (!injectedNamesToPlugins.hasOwnProperty(pluginName)) {
diff --git a/packages/react-dom/src/__tests__/ReactDOM-test.js b/packages/react-dom/src/__tests__/ReactDOM-test.js
index dd7f97484b..15d3d9b4dc 100644
--- a/packages/react-dom/src/__tests__/ReactDOM-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOM-test.js
@@ -377,25 +377,6 @@ describe('ReactDOM', () => {
     }
   });
 
-  // https://github.com/facebook/react/issues/11689
-  it('should warn when attempting to inject an event plugin', () => {
-    expect(() => {
-      ReactDOM.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED.EventPluginHub.injection.injectEventPluginsByName(
-        {
-          TapEventPlugin: {
-            extractEvents() {},
-          },
-        },
-      );
-    }).toLowPriorityWarnDev(
-      'Injecting custom event plugins (TapEventPlugin) is deprecated ' +
-        'and will not work in React 17+. Please update your code ' +
-        'to not depend on React internals. The stack trace for this ' +
-        'warning should reveal the library that is using them. ' +
-        'See https://github.com/facebook/react/issues/11689 for a discussion.',
-    );
-  });
-
   it('throws in DEV if jsdom is destroyed by the time setState() is called', () => {
     class App extends React.Component {
       state = {x: 1};
diff --git a/packages/react-dom/src/__tests__/TapEventPlugin-test.internal.js b/packages/react-dom/src/__tests__/TapEventPlugin-test.internal.js
index bd5b097915..b822da91b0 100644
--- a/packages/react-dom/src/__tests__/TapEventPlugin-test.internal.js
+++ b/packages/react-dom/src/__tests__/TapEventPlugin-test.internal.js
@@ -86,13 +86,9 @@ describe('TapEventPlugin', () => {
 
     idCallOrder = [];
     tapMoveThreshold = TapEventPlugin.tapMoveThreshold;
-    expect(() =>
-      EventPluginHub.injection.injectEventPluginsByName({
-        TapEventPlugin: TapEventPlugin,
-      }),
-    ).toLowPriorityWarnDev(
-      'Injecting custom event plugins (TapEventPlugin) is deprecated',
-    );
+    EventPluginHub.injection.injectEventPluginsByName({
+      TapEventPlugin: TapEventPlugin,
+    });
   });
 
   /**
diff --git a/packages/react-dom/src/client/ReactDOM.js b/packages/react-dom/src/client/ReactDOM.js
index a39bafdf24..a2576e2e70 100644
--- a/packages/react-dom/src/client/ReactDOM.js
+++ b/packages/react-dom/src/client/ReactDOM.js
@@ -1300,13 +1300,6 @@ const ReactDOM: Object = {
   },
 };
 
-if (__DEV__) {
-  // Show deprecation warnings as we don't want to support injection forever.
-  // We do it now to let the internal injection happen without warnings.
-  // https://github.com/facebook/react/issues/11689
-  EventPluginRegistry.enableWarningOnInjection();
-}
-
 type RootOptions = {
   hydrate?: boolean,
 };