diff --git a/packages/material_ui/lib/src/expansion_tile.dart b/packages/material_ui/lib/src/expansion_tile.dart
index 3d59612ccc4..b77fbad2a0f 100644
--- a/packages/material_ui/lib/src/expansion_tile.dart
+++ b/packages/material_ui/lib/src/expansion_tile.dart
@@ -693,7 +693,9 @@ class _ExpansionTileState extends State<ExpansionTile> {
       return Semantics(
         // Live region used to announce state changes (e.g., "expanded" or "collapsed")
         // without taking focus.
-        // blockNode prevents this node from being part of the focus traversal.
+        // The container ensures the live region forms the node that blockNode
+        // removes from focus traversal.
+        container: true,
         label: semanticsHint,
         liveRegion: true,
         accessibilityFocusBlockType: AccessibilityFocusBlockType.blockNode,
diff --git a/packages/material_ui/pending_changelogs/change_2026_08_06_expansion_tile_widget_span.yaml b/packages/material_ui/pending_changelogs/change_2026_08_06_expansion_tile_widget_span.yaml
new file mode 100644
index 00000000000..8b397ca1d4f
--- /dev/null
+++ b/packages/material_ui/pending_changelogs/change_2026_08_06_expansion_tile_widget_span.yaml
@@ -0,0 +1,3 @@
+changelog: |
+  - Fixes an Android semantics assertion when an `ExpansionTile` is embedded in a `WidgetSpan`.
+version: patch
diff --git a/packages/material_ui/test/expansion_tile_test.dart b/packages/material_ui/test/expansion_tile_test.dart
index bfdb8b020b1..ee3436261f6 100644
--- a/packages/material_ui/test/expansion_tile_test.dart
+++ b/packages/material_ui/test/expansion_tile_test.dart
@@ -2230,6 +2230,34 @@ void main() {
     );
   });
   group('Semantics tests for android platform', () {
+    // Regression test for https://github.com/flutter/flutter/issues/188298.
+    testWidgets('ExpansionTile supports being embedded in a WidgetSpan', (
+      WidgetTester tester,
+    ) async {
+      final SemanticsHandle handle = tester.ensureSemantics();
+
+      await tester.pumpWidget(
+        const MaterialApp(
+          home: Scaffold(
+            body: Text.rich(
+              TextSpan(
+                children: <InlineSpan>[
+                  WidgetSpan(
+                    child: ExpansionTile(
+                      title: Text('Header'),
+                      children: <Widget>[Text('Details')],
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        ),
+      );
+      expect(find.text('Header'), findsOneWidget);
+      handle.dispose();
+    }, variant: const TargetPlatformVariant(<TargetPlatform>{TargetPlatform.android}));
+
     testWidgets('Semantics liveregion updates when expansion state changes', (
       WidgetTester tester,
     ) async {