diff --git a/packages/upgrade/src/common/src/constants.ts b/packages/upgrade/src/common/src/constants.ts
index 7c9c5d0c8f766..640d23adf0ea0 100644
--- a/packages/upgrade/src/common/src/constants.ts
+++ b/packages/upgrade/src/common/src/constants.ts
@@ -15,6 +15,7 @@ export const $INJECTOR = '$injector';
 export const $INTERVAL = '$interval';
 export const $PARSE = '$parse';
 export const $PROVIDE = '$provide';
+export const $ROOT_ELEMENT = '$rootElement';
 export const $ROOT_SCOPE = '$rootScope';
 export const $SCOPE = '$scope';
 export const $TEMPLATE_CACHE = '$templateCache';
diff --git a/packages/upgrade/src/common/src/util.ts b/packages/upgrade/src/common/src/util.ts
index 2c39d79eac6c0..0edc5c72f996d 100644
--- a/packages/upgrade/src/common/src/util.ts
+++ b/packages/upgrade/src/common/src/util.ts
@@ -8,8 +8,8 @@
 
 import {Injector, Type} from '@angular/core';
 
-import {element as angularElement, IInjectorService, INgModelController} from './angular1';
-import {DOWNGRADED_MODULE_COUNT_KEY, UPGRADE_APP_TYPE_KEY} from './constants';
+import {element as angularElement, IAugmentedJQuery, IInjectorService, INgModelController, IRootScopeService} from './angular1';
+import {$ROOT_ELEMENT, $ROOT_SCOPE, DOWNGRADED_MODULE_COUNT_KEY, UPGRADE_APP_TYPE_KEY} from './constants';
 
 const DIRECTIVE_PREFIX_REGEXP = /^(?:x|data)[:\-_]/i;
 const DIRECTIVE_SPECIAL_CHARS_REGEXP = /[:\-_]+(.)/g;
@@ -42,6 +42,17 @@ export function controllerKey(name: string): string {
   return '$' + name + 'Controller';
 }
 
+// Destroy an AngularJS app given the app `$injector`.
+//
+// NOTE: Destroying an app is not officially supported by AngularJS, but we do our best.
+export function destroyApp($injector: IInjectorService): void {
+  const $rootElement: IAugmentedJQuery = $injector.get($ROOT_ELEMENT);
+  const $rootScope: IRootScopeService = $injector.get($ROOT_SCOPE);
+
+  $rootScope.$destroy();
+  cleanData($rootElement[0] as Element);
+}
+
 export function directiveNormalize(name: string): string {
   return name.replace(DIRECTIVE_PREFIX_REGEXP, '')
       .replace(DIRECTIVE_SPECIAL_CHARS_REGEXP, (_, letter) => letter.toUpperCase());
diff --git a/packages/upgrade/src/dynamic/src/upgrade_adapter.ts b/packages/upgrade/src/dynamic/src/upgrade_adapter.ts
index bbb304e494c00..05a489ea14da8 100644
--- a/packages/upgrade/src/dynamic/src/upgrade_adapter.ts
+++ b/packages/upgrade/src/dynamic/src/upgrade_adapter.ts
@@ -13,7 +13,7 @@ import {bootstrap, element as angularElement, IAngularBootstrapConfig, IAugmente
 import {$$TESTABILITY, $COMPILE, $INJECTOR, $ROOT_SCOPE, COMPILER_KEY, INJECTOR_KEY, LAZY_MODULE_REF, NG_ZONE_KEY, UPGRADE_APP_TYPE_KEY} from '../../common/src/constants';
 import {downgradeComponent} from '../../common/src/downgrade_component';
 import {downgradeInjectable} from '../../common/src/downgrade_injectable';
-import {controllerKey, Deferred, LazyModuleRef, onError, UpgradeAppType} from '../../common/src/util';
+import {destroyApp, controllerKey, Deferred, LazyModuleRef, onError, UpgradeAppType} from '../../common/src/util';
 
 import {UpgradeNg1ComponentAdapterBuilder} from './upgrade_ng1_adapter';
 
@@ -620,6 +620,12 @@ export class UpgradeAdapter {
                     rootScope.$on('$destroy', () => {
                       subscription.unsubscribe();
                     });
+
+                    // Destroy the AngularJS app once the associated `PlatformRef` is destroyed.
+                    // This does not happen in a typical SPA scenario, but it might be useful for
+                    // other usecases where desposing of an Angular/AngularJS app is necessary (such
+                    // as micro-frontends, Hot Module Replacement (HMR), etc.).
+                    platformRef.onDestroy(() => destroyApp(ng1Injector));
                   });
             })
             .catch((e) => this.ng2BootstrapDeferred.reject(e));
diff --git a/packages/upgrade/static/src/downgrade_module.ts b/packages/upgrade/static/src/downgrade_module.ts
index bde2fe8db93c2..938a3ea06d91e 100644
--- a/packages/upgrade/static/src/downgrade_module.ts
+++ b/packages/upgrade/static/src/downgrade_module.ts
@@ -6,12 +6,12 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Injector, NgModuleFactory, NgModuleRef, StaticProvider} from '@angular/core';
+import {Injector, NgModuleFactory, NgModuleRef, PlatformRef, StaticProvider} from '@angular/core';
 import {platformBrowser} from '@angular/platform-browser';
 
 import {IInjectorService, IProvideService, module_ as angularModule} from '../../src/common/src/angular1';
 import {$INJECTOR, $PROVIDE, DOWNGRADED_MODULE_COUNT_KEY, INJECTOR_KEY, LAZY_MODULE_REF, UPGRADE_APP_TYPE_KEY, UPGRADE_MODULE_NAME} from '../../src/common/src/constants';
-import {getDowngradedModuleCount, isFunction, LazyModuleRef, UpgradeAppType} from '../../src/common/src/util';
+import {destroyApp, getDowngradedModuleCount, isFunction, LazyModuleRef, UpgradeAppType} from '../../src/common/src/util';
 
 import {angular1Providers, setTempInjectorRef} from './angular1_providers';
 import {NgAdapterInjector} from './util';
@@ -167,6 +167,12 @@ export function downgradeModule<T>(moduleFactoryOrBootstrapFn: NgModuleFactory<T
                   injector = result.injector = new NgAdapterInjector(ref.injector);
                   injector.get($INJECTOR);
 
+                  // Destroy the AngularJS app once the associated `PlatformRef` is destroyed. This
+                  // does not happen in a typical SPA scenario, but it might be useful for other
+                  // usecases where desposing of an Angular/AngularJS app is necessary (such as
+                  // micro-frontends, Hot Module Replacement (HMR), etc.).
+                  injector.get(PlatformRef).onDestroy(() => destroyApp($injector));
+
                   return injector;
                 })
               };
diff --git a/packages/upgrade/static/src/upgrade_module.ts b/packages/upgrade/static/src/upgrade_module.ts
index 899d5ab59c4c0..90d5043949124 100644
--- a/packages/upgrade/static/src/upgrade_module.ts
+++ b/packages/upgrade/static/src/upgrade_module.ts
@@ -6,11 +6,11 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Injector, isDevMode, NgModule, NgZone, Testability} from '@angular/core';
+import {Injector, isDevMode, NgModule, NgZone, PlatformRef, Testability} from '@angular/core';
 
 import {bootstrap, element as angularElement, IInjectorService, IIntervalService, IProvideService, ITestabilityService, module_ as angularModule} from '../../src/common/src/angular1';
 import {$$TESTABILITY, $DELEGATE, $INJECTOR, $INTERVAL, $PROVIDE, INJECTOR_KEY, LAZY_MODULE_REF, UPGRADE_APP_TYPE_KEY, UPGRADE_MODULE_NAME} from '../../src/common/src/constants';
-import {controllerKey, LazyModuleRef, UpgradeAppType} from '../../src/common/src/util';
+import {destroyApp, controllerKey, LazyModuleRef, UpgradeAppType} from '../../src/common/src/util';
 
 import {angular1Providers, setTempInjectorRef} from './angular1_providers';
 import {NgAdapterInjector} from './util';
@@ -155,7 +155,13 @@ export class UpgradeModule {
       /** The root `Injector` for the upgrade application. */
       injector: Injector,
       /** The bootstrap zone for the upgrade application */
-      public ngZone: NgZone) {
+      public ngZone: NgZone,
+      /**
+       * The owning `NgModuleRef`s `PlatformRef` instance.
+       * This is used to tie the lifecycle of the bootstrapped AngularJS apps to that of the Angular
+       * `PlatformRef`.
+       */
+      private platformRef: PlatformRef) {
     this.injector = new NgAdapterInjector(injector);
   }
 
@@ -272,6 +278,12 @@ export class UpgradeModule {
                   $rootScope.$on('$destroy', () => {
                     subscription.unsubscribe();
                   });
+
+                  // Destroy the AngularJS app once the associated `PlatformRef` is destroyed. This
+                  // does not happen in a typical SPA scenario, but it might be useful for other
+                  // usecases where desposing of an Angular/AngularJS app is necessary (such as
+                  // micro-frontends, Hot Module Replacement (HMR), etc.).
+                  this.platformRef.onDestroy(() => destroyApp($injector));
                 }, 0);
               }
             ]);