diff --git a/packages/flutter/lib/src/widgets/navigator.dart b/packages/flutter/lib/src/widgets/navigator.dart
index 1453c92d766..65c199c13e4 100644
--- a/packages/flutter/lib/src/widgets/navigator.dart
+++ b/packages/flutter/lib/src/widgets/navigator.dart
@@ -3163,6 +3163,10 @@ class _RouteEntry extends RouteTransitionRecord {
   _RoutePlaceholder? lastAnnouncedNextRoute = notAnnounced; // last argument to Route.didChangeNext
   int? lastFocusNode; // The last focused semantic node for the route entry.
 
+  // Whether this route is removed without using a Navigator.pages api.
+  // For example, Navigator.pop or Navigator.pushReplacement.
+  bool imperativeRemoval = false;
+
   /// Restoration ID to be used for the encapsulating route when restoration is
   /// enabled for it or null if restoration cannot be enabled for it.
   String? get restorationId {
@@ -3302,10 +3306,6 @@ class _RouteEntry extends RouteTransitionRecord {
       return false;
     }
     route.onPopInvokedWithResult(true, pendingResult);
-    if (pageBased) {
-      final Page<Object?> page = route.settings as Page<Object?>;
-      navigator.widget.onDidRemovePage?.call(page);
-    }
     pendingResult = null;
     return true;
   }
@@ -3322,8 +3322,14 @@ class _RouteEntry extends RouteTransitionRecord {
     required Route<dynamic>? previousPresent,
   }) {
     assert(navigator._debugLocked);
-    assert(route._navigator == navigator);
-    currentState = _RouteLifecycle.removing;
+    if (route._navigator == navigator) {
+      currentState = _RouteLifecycle.removing;
+    } else {
+      // This route is still waiting to be added while a top-most push or pop
+      // animation is still on-going. In this case, this route can be disposed
+      // directly since nothing has been initialized yet.
+      currentState = _RouteLifecycle.dispose;
+    }
     if (_reportRemovalToObserver) {
       navigator._observedRouteDeletions.add(_NavigatorRemoveObservation(route, previousPresent));
     }
@@ -3343,21 +3349,17 @@ class _RouteEntry extends RouteTransitionRecord {
 
   Object? pendingResult;
 
-  void pop<T>(T? result) {
+  void pop<T>(T? result, {required bool imperativeRemoval}) {
     assert(isPresent);
     pendingResult = result;
     currentState = _RouteLifecycle.pop;
+    this.imperativeRemoval = imperativeRemoval;
   }
 
   bool _reportRemovalToObserver = true;
 
   // Route completes with `result` and is removed.
-  void complete<T>(T result, {bool isReplaced = false}) {
-    assert(
-      !pageBased || isWaitingForExitingDecision,
-      'A page-based route cannot be completed using imperative api, provide a '
-      'new list without the corresponding Page to Navigator.pages instead. ',
-    );
+  void complete<T>(T result, {required bool isReplaced, required bool imperativeRemoval}) {
     if (currentState.index >= _RouteLifecycle.remove.index) {
       return;
     }
@@ -3365,6 +3367,7 @@ class _RouteEntry extends RouteTransitionRecord {
     _reportRemovalToObserver = !isReplaced;
     pendingResult = result;
     currentState = _RouteLifecycle.complete;
+    this.imperativeRemoval = imperativeRemoval;
   }
 
   void finalize() {
@@ -3529,7 +3532,7 @@ class _RouteEntry extends RouteTransitionRecord {
       final bool popResult = route.didPop(result);
       assert(!popResult);
     }
-    pop<dynamic>(result);
+    pop<dynamic>(result, imperativeRemoval: false);
     _isWaitingForExitingDecision = false;
   }
 
@@ -3541,7 +3544,7 @@ class _RouteEntry extends RouteTransitionRecord {
       'been made or it does not require an explicit decision on how to transition '
       'out.',
     );
-    complete<dynamic>(result);
+    complete<dynamic>(result, isReplaced: false, imperativeRemoval: false);
     _isWaitingForExitingDecision = false;
   }
 
@@ -4491,21 +4494,21 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
             navigator: this,
             previousPresent: _getRouteBefore(index, _RouteEntry.willBePresentPredicate)?.route,
           );
-          assert(entry.currentState == _RouteLifecycle.removing);
+          assert(entry.currentState.index >= _RouteLifecycle.removing.index);
           continue;
         case _RouteLifecycle.removing:
           if (!canRemoveOrAdd && next != null) {
             // We aren't allowed to remove this route yet.
             break;
           }
-          if (entry.pageBased) {
-            widget.onDidRemovePage?.call(entry.route.settings as Page<Object?>);
-          }
           entry.currentState = _RouteLifecycle.dispose;
           continue;
         case _RouteLifecycle.dispose:
           // Delay disposal until didChangeNext/didChangePrevious have been sent.
           toBeDisposed.add(_history.removeAt(index));
+          if (entry.pageBased && entry.imperativeRemoval) {
+            widget.onDidRemovePage?.call(entry.route.settings as Page<Object?>);
+          }
           entry = next;
         case _RouteLifecycle.disposing:
         case _RouteLifecycle.disposed:
@@ -5185,7 +5188,9 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
       'Navigator has no active routes to replace.',
     );
     assert(entry.currentState == _RouteLifecycle.pushReplace);
-    _history.lastWhere(_RouteEntry.isPresentPredicate).complete(result, isReplaced: true);
+    _history
+        .lastWhere(_RouteEntry.isPresentPredicate)
+        .complete(result, isReplaced: true, imperativeRemoval: true);
     _history.add(entry);
     _flushHistoryUpdates();
     assert(() {
@@ -5284,7 +5289,7 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
     _history.add(entry);
     while (index >= 0 && !predicate(_history[index].route)) {
       if (_history[index].isPresent) {
-        _history[index].complete(null);
+        _history[index].complete(null, isReplaced: false, imperativeRemoval: true);
       }
       index -= 1;
     }
@@ -5369,7 +5374,7 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
     );
     final bool wasCurrent = oldRoute.isCurrent;
     _history.insert(index + 1, entry);
-    _history[index].complete(null, isReplaced: true);
+    _history[index].complete(null, isReplaced: true, imperativeRemoval: true);
     _flushHistoryUpdates();
     assert(() {
       _debugLocked = false;
@@ -5459,7 +5464,7 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
     }
     assert(index >= 0, 'There are no routes below the specified anchorRoute.');
     _history.insert(index + 1, entry);
-    _history[index].complete(null, isReplaced: true);
+    _history[index].complete(null, isReplaced: true, imperativeRemoval: true);
     _flushHistoryUpdates();
     assert(() {
       _debugLocked = false;
@@ -5582,7 +5587,7 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
         entry.route.onPopInvokedWithResult(true, result);
       }
     } else {
-      entry.pop<T>(result);
+      entry.pop<T>(result, imperativeRemoval: true);
       assert(entry.currentState == _RouteLifecycle.pop);
     }
     if (entry.currentState == _RouteLifecycle.pop) {
@@ -5634,7 +5639,7 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
     assert(route._navigator == this);
     final bool wasCurrent = route.isCurrent;
     final _RouteEntry entry = _history.firstWhere(_RouteEntry.isRoutePredicate(route));
-    entry.complete(result);
+    entry.complete(result, isReplaced: false, imperativeRemoval: true);
     _flushHistoryUpdates(rearrangeOverlay: false);
     assert(() {
       _debugLocked = false;
@@ -5671,7 +5676,7 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
       index -= 1;
     }
     assert(index >= 0, 'There are no routes below the specified anchorRoute.');
-    _history[index].complete(result);
+    _history[index].complete(result, isReplaced: false, imperativeRemoval: true);
     _flushHistoryUpdates(rearrangeOverlay: false);
     assert(() {
       _debugLocked = false;
diff --git a/packages/flutter/test/widgets/navigator_on_did_remove_page_test.dart b/packages/flutter/test/widgets/navigator_on_did_remove_page_test.dart
new file mode 100644
index 00000000000..2e20adb5acc
--- /dev/null
+++ b/packages/flutter/test/widgets/navigator_on_did_remove_page_test.dart
@@ -0,0 +1,127 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  Future<void> buildPages(
+    List<Page<void>> pages,
+    WidgetTester tester, {
+    GlobalKey<NavigatorState>? navKey,
+    required List<Page<void>> removedPage,
+  }) {
+    return tester.pumpWidget(
+      MediaQuery(
+        data: MediaQueryData.fromView(tester.view),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: Navigator(key: navKey, pages: pages, onDidRemovePage: removedPage.add),
+        ),
+      ),
+    );
+  }
+
+  testWidgets('Page API will not call onDidRemovePage', (WidgetTester tester) async {
+    final List<Page<void>> removedPages = <Page<void>>[];
+
+    const MaterialPage<void> page = MaterialPage<void>(
+      key: ValueKey<String>('page'),
+      child: Text('page'),
+    );
+    const MaterialPage<void> page1 = MaterialPage<void>(
+      key: ValueKey<String>('page1'),
+      child: Text('page1'),
+    );
+    const MaterialPage<void> page2 = MaterialPage<void>(
+      key: ValueKey<String>('page2'),
+      child: Text('page2'),
+    );
+    const MaterialPage<void> page3 = MaterialPage<void>(
+      key: ValueKey<String>('page3'),
+      child: Text('page3'),
+    );
+    const MaterialPage<void> page4 = MaterialPage<void>(
+      key: ValueKey<String>('page4'),
+      child: Text('page4'),
+    );
+    const MaterialPage<void> page5 = MaterialPage<void>(
+      key: ValueKey<String>('page5'),
+      child: Text('page5'),
+    );
+    const MaterialPage<void> page6 = MaterialPage<void>(
+      key: ValueKey<String>('page6'),
+      child: Text('page6'),
+    );
+    await buildPages(<Page<void>>[page], tester, removedPage: removedPages);
+
+    expect(find.text('page'), findsOneWidget);
+
+    await buildPages(<Page<void>>[page, page1, page2, page3], tester, removedPage: removedPages);
+    await buildPages(<Page<void>>[page, page4, page5, page6], tester, removedPage: removedPages);
+    await tester.pumpAndSettle();
+    expect(find.text('page6'), findsOneWidget);
+    expect(removedPages, isEmpty);
+
+    await buildPages(<Page<void>>[page, page4, page5], tester, removedPage: removedPages);
+    await tester.pumpAndSettle();
+    expect(find.text('page5'), findsOneWidget);
+    expect(removedPages, isEmpty);
+
+    await buildPages(<Page<void>>[page], tester, removedPage: removedPages);
+    await tester.pumpAndSettle();
+    expect(find.text('page'), findsOneWidget);
+    expect(removedPages, isEmpty);
+  });
+
+  testWidgets('pop calls onDidRemovePage', (WidgetTester tester) async {
+    final GlobalKey<NavigatorState> key = GlobalKey<NavigatorState>();
+    final List<Page<void>> removedPage = <Page<void>>[];
+
+    const MaterialPage<void> page = MaterialPage<void>(
+      key: ValueKey<String>('page'),
+      child: Text('page'),
+    );
+    const MaterialPage<void> page1 = MaterialPage<void>(
+      key: ValueKey<String>('page1'),
+      child: Text('page1'),
+    );
+    await buildPages(<Page<void>>[page, page1], tester, removedPage: removedPage, navKey: key);
+
+    expect(find.text('page1'), findsOneWidget);
+
+    key.currentState!.pop();
+    await tester.pumpAndSettle();
+    expect(find.text('page'), findsOneWidget);
+    expect(removedPage, <Page<void>>[page1]);
+  });
+
+  testWidgets('pushReplacement calls onDidRemovePage', (WidgetTester tester) async {
+    final GlobalKey<NavigatorState> key = GlobalKey<NavigatorState>();
+    final List<Page<void>> removedPage = <Page<void>>[];
+
+    const MaterialPage<void> page = MaterialPage<void>(
+      key: ValueKey<String>('page'),
+      child: Text('page'),
+    );
+    const MaterialPage<void> page1 = MaterialPage<void>(
+      key: ValueKey<String>('page1'),
+      child: Text('page1'),
+    );
+    await buildPages(<Page<void>>[page, page1], tester, removedPage: removedPage, navKey: key);
+
+    expect(find.text('page1'), findsOneWidget);
+
+    key.currentState!.pushReplacement(
+      MaterialPageRoute<void>(
+        builder: (_) {
+          return const Text('new page');
+        },
+      ),
+    );
+    await tester.pumpAndSettle();
+    expect(find.text('new page'), findsOneWidget);
+    expect(removedPage, <Page<void>>[page1]);
+  });
+}
diff --git a/packages/flutter/test/widgets/navigator_test.dart b/packages/flutter/test/widgets/navigator_test.dart
index b69d131040d..067a81335a1 100644
--- a/packages/flutter/test/widgets/navigator_test.dart
+++ b/packages/flutter/test/widgets/navigator_test.dart
@@ -250,40 +250,91 @@ void main() {
     expect(tester.widget<Overlay>(find.byType(Overlay)).clipBehavior, Clip.none);
   });
 
-  testWidgets('Navigator should call observer.didPop when pops page-based routes', (
-    WidgetTester tester,
-  ) async {
+  testWidgets('Navigator can set clip behavior', (WidgetTester tester) async {
     const MaterialPage<void> page = MaterialPage<void>(child: Text('page'));
-    const MaterialPage<void> page1 = MaterialPage<void>(child: Text('page1'));
-    final List<Page<void>> pages = <Page<void>>[page, page1];
-    final _MockNavigatorObserver observer = _MockNavigatorObserver();
-    final GlobalKey<NavigatorState> nav = GlobalKey<NavigatorState>();
+    await tester.pumpWidget(
+      MediaQuery(
+        data: MediaQueryData.fromView(tester.view),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: Navigator(pages: const <Page<void>>[page], onPopPage: (_, _) => false),
+        ),
+      ),
+    );
+    // Default to hard edge.
+    expect(tester.widget<Overlay>(find.byType(Overlay)).clipBehavior, Clip.hardEdge);
+
     await tester.pumpWidget(
       MediaQuery(
         data: MediaQueryData.fromView(tester.view),
         child: Directionality(
           textDirection: TextDirection.ltr,
           child: Navigator(
-            key: nav,
-            pages: pages,
-            observers: <NavigatorObserver>[observer],
-            onPopPage: (Route<dynamic> route, dynamic result) {
-              route.didPop(result);
-              pages.remove(route.settings);
-              return true;
-            },
+            pages: const <Page<void>>[page],
+            clipBehavior: Clip.none,
+            onPopPage: (_, _) => false,
           ),
         ),
       ),
     );
+    expect(tester.widget<Overlay>(find.byType(Overlay)).clipBehavior, Clip.none);
+  });
 
-    expect(find.text('page1'), findsOneWidget);
+  testWidgets('Can remove page before they are added', (WidgetTester tester) async {
+    final GlobalKey<NavigatorState> key = GlobalKey<NavigatorState>();
+    Future<void> buildPages(List<Page<void>> pages) {
+      return tester.pumpWidget(
+        MediaQuery(
+          data: MediaQueryData.fromView(tester.view),
+          child: Directionality(
+            textDirection: TextDirection.ltr,
+            child: Navigator(key: key, pages: pages, onDidRemovePage: (_) {}),
+          ),
+        ),
+      );
+    }
+
+    const MaterialPage<void> page = MaterialPage<void>(
+      key: ValueKey<String>('page'),
+      child: Text('page'),
+    );
+    const MaterialPage<void> page1 = MaterialPage<void>(
+      key: ValueKey<String>('page1'),
+      child: Text('page1'),
+    );
+    const MaterialPage<void> page2 = MaterialPage<void>(
+      key: ValueKey<String>('page2'),
+      child: Text('page2'),
+    );
+    const MaterialPage<void> page3 = MaterialPage<void>(
+      key: ValueKey<String>('page3'),
+      child: Text('page3'),
+    );
+    const MaterialPage<void> page4 = MaterialPage<void>(
+      key: ValueKey<String>('page4'),
+      child: Text('page4'),
+    );
+    const MaterialPage<void> page5 = MaterialPage<void>(
+      key: ValueKey<String>('page5'),
+      child: Text('page5'),
+    );
+    const MaterialPage<void> page6 = MaterialPage<void>(
+      key: ValueKey<String>('page6'),
+      child: Text('page6'),
+    );
+    await buildPages(<Page<void>>[page]);
 
-    observer._invocations.clear();
-    nav.currentState!.pop();
-    await tester.pumpAndSettle();
     expect(find.text('page'), findsOneWidget);
-    observer._checkInvocations(const <Symbol>[#didPop, #didChangeTop]);
+
+    await buildPages(<Page<void>>[page, page1, page2, page3]);
+
+    // In mid transition;
+    await tester.pump(const Duration(microseconds: 150));
+    // Cause page1 and page2 to be removed before they are added.
+    await buildPages(<Page<void>>[page, page4, page5, page6]);
+    await tester.pumpAndSettle();
+    expect(find.text('page6'), findsOneWidget);
+    expect(tester.takeException(), isNull);
   });
 
   testWidgets('Zero transition page-based route correctly notifies observers when it is popped', (