diff --git a/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/accessibility.dart b/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/accessibility.dart
index c4803098ee0..f0ba1d480a4 100644
--- a/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/accessibility.dart
+++ b/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/accessibility.dart
@@ -51,6 +51,15 @@ class AccessibilityAnnouncements {
   /// accouncements assertively.
   final DomHTMLElement _assertiveElement;
 
+  /// Whether to append a non-breaking space to the end of the message
+  /// before outputting it.
+  ///
+  /// It's used to work around a VoiceOver bug where announcing the same message
+  /// repeatedly results in subsequent messages not being announced despite the
+  /// fact that the previous announcement was already removed from the DOM a
+  /// long while back. See https://github.com/flutter/flutter/issues/142250.
+  bool _appendSpace = false;
+
   /// Looks up the element used to announce messages of the given [assertiveness].
   DomHTMLElement ariaLiveElementFor(Assertiveness assertiveness) {
     switch (assertiveness) {
@@ -84,7 +93,9 @@ class AccessibilityAnnouncements {
     final DomHTMLElement ariaLiveElement = ariaLiveElementFor(assertiveness);
 
     final DomHTMLDivElement messageElement = createDomHTMLDivElement();
-    messageElement.text = message;
+    // See the doc-comment for [_appendSpace] for the rationale.
+    messageElement.text = _appendSpace ? '$message\u00A0' : message;
+    _appendSpace = !_appendSpace;
     ariaLiveElement.append(messageElement);
     Timer(liveMessageDuration, () => messageElement.remove());
   }
diff --git a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_announcement_test.dart b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_announcement_test.dart
index 0ac51c51c5d..a9c4e9fa945 100644
--- a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_announcement_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_announcement_test.dart
@@ -91,21 +91,38 @@ void testMain() {
       expectNoMessages();
     });
 
-    test('Rapid-fire messages are each announced.', () async {
+    test('Rapid-fire messages are each announced', () async {
       sendAnnouncementMessage(message: 'Hello');
       expectMessages(polite: 'Hello');
 
       await Future<void>.delayed(liveMessageDuration * 0.5);
       sendAnnouncementMessage(message: 'There');
-      expectMessages(polite: 'HelloThere');
+      expectMessages(polite: 'HelloThere\u00A0');
 
       await Future<void>.delayed(liveMessageDuration * 0.6);
-      expectMessages(polite: 'There');
+      expectMessages(polite: 'There\u00A0');
 
       await Future<void>.delayed(liveMessageDuration * 0.5);
       expectNoMessages();
     });
 
+    test('Repeated announcements are modified to ensure screen readers announce them', () async {
+      sendAnnouncementMessage(message: 'Hello');
+      expectMessages(polite: 'Hello');
+      await Future<void>.delayed(liveMessageDuration);
+      expectNoMessages();
+
+      sendAnnouncementMessage(message: 'Hello');
+      expectMessages(polite: 'Hello\u00A0');
+      await Future<void>.delayed(liveMessageDuration);
+      expectNoMessages();
+
+      sendAnnouncementMessage(message: 'Hello');
+      expectMessages(polite: 'Hello');
+      await Future<void>.delayed(liveMessageDuration);
+      expectNoMessages();
+    });
+
     test('announce() polite', () async {
       accessibilityAnnouncements.announce('polite message', Assertiveness.polite);
       expectMessages(polite: 'polite message');