diff --git a/mobile/lib/features/channels/reply_activity_handoff.dart b/mobile/lib/features/channels/reply_activity_handoff.dart
index 9b460ec05b..cb12ea5443 100644
--- a/mobile/lib/features/channels/reply_activity_handoff.dart
+++ b/mobile/lib/features/channels/reply_activity_handoff.dart
@@ -45,9 +45,16 @@ class ReplyActivityHandoff extends HookWidget {
     }, [working, reducedMotion]);
     final animated = useAnimation(controller);
     final progress = reducedMotion ? (working ? 0.0 : 1.0) : animated;
-    final style = context.textTheme.labelMedium?.copyWith(
-      color: context.colors.onSurfaceVariant,
+    // Match Text's inherited style and platform Bold Text override so the
+    // measured box fits the glyphs that are actually rendered.
+    var style = DefaultTextStyle.of(context).style.merge(
+      context.textTheme.labelMedium?.copyWith(
+        color: context.colors.onSurfaceVariant,
+      ),
     );
+    if (MediaQuery.boldTextOf(context)) {
+      style = style.merge(const TextStyle(fontWeight: FontWeight.bold));
+    }
     return LayoutBuilder(
       builder: (context, constraints) {
         final text = TextPainter(
diff --git a/mobile/test/features/channels/reply_summary_bold_text_test.dart b/mobile/test/features/channels/reply_summary_bold_text_test.dart
new file mode 100644
index 0000000000..7bf35dd1d2
--- /dev/null
+++ b/mobile/test/features/channels/reply_summary_bold_text_test.dart
@@ -0,0 +1,85 @@
+import 'package:buzz/features/channels/reply_summary_link.dart';
+import 'package:buzz/features/channels/timeline_message.dart';
+import 'package:buzz/shared/profile/user_cache_provider.dart';
+import 'package:buzz/shared/profile/user_profile.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../helpers/widget_helpers.dart';
+
+void main() {
+  setUpAll(() async {
+    // Ahem has identical regular/bold metrics and hides this regression.
+    final font = FontLoader('Inter')
+      ..addFont(rootBundle.load('assets/fonts/InterVariable.ttf'));
+    await font.load();
+  });
+
+  for (final working in [false, true]) {
+    for (final scale in [1.0, 2.0]) {
+      testWidgets(
+        'reply label honors Bold Text: working=$working scale=$scale',
+        (tester) async {
+          Widget view(bool bold) => WidgetHelpers.testable(
+            overrides: [userCacheProvider.overrideWith(_Profiles.new)],
+            child: MediaQuery(
+              data: MediaQueryData(
+                boldText: bold,
+                textScaler: TextScaler.linear(scale),
+              ),
+              child: Align(
+                alignment: Alignment.topLeft,
+                child: SizedBox(
+                  width: 400,
+                  child: ReplySummaryLink(
+                    summary: const ThreadSummary(
+                      threadHeadId: 'root',
+                      replyCount: 12,
+                      participantPubkeys: ['participant'],
+                    ),
+                    working: working ? const ['participant'] : const [],
+                    onTap: () {},
+                  ),
+                ),
+              ),
+            ),
+          );
+
+          for (final bold in [false, true, false]) {
+            await tester.pumpWidget(view(bold));
+            final paragraph = tester.renderObject<RenderParagraph>(
+              find.text('12 replies'),
+            );
+            final expected = TextPainter(
+              text: paragraph.text,
+              textDirection: paragraph.textDirection,
+              textScaler: paragraph.textScaler,
+            )..layout();
+            // The entire one-line label fits at this viewport; its allocated
+            // width must match the text actually rendered, including bold.
+            expect(paragraph.size.width, closeTo(expected.width, 0.01));
+            expect(paragraph.size.height, closeTo(expected.height, 0.01));
+            expect(paragraph.didExceedMaxLines, isFalse);
+            if (bold) {
+              expect(paragraph.text.style!.fontWeight, FontWeight.bold);
+            }
+            expected.dispose();
+            expect(tester.takeException(), isNull);
+          }
+        },
+      );
+    }
+  }
+}
+
+class _Profiles extends UserCacheNotifier {
+  @override
+  Map<String, UserProfile> build() => const {
+    'participant': UserProfile(
+      pubkey: 'participant',
+      displayName: 'Participant',
+    ),
+  };
+}