diff --git a/packages/flutter/lib/src/material/scrollbar.dart b/packages/flutter/lib/src/material/scrollbar.dart
index c274695eed3..561c3917dd4 100644
--- a/packages/flutter/lib/src/material/scrollbar.dart
+++ b/packages/flutter/lib/src/material/scrollbar.dart
@@ -326,7 +326,8 @@ class _MaterialScrollbarState extends RawScrollbarState<_MaterialScrollbar> {
   MaterialStateProperty<double> get _thickness {
     return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
       if (states.contains(MaterialState.hovered) && _trackVisibility.resolve(states)) {
-        return _scrollbarTheme.thickness?.resolve(states)
+        return widget.thickness
+          ?? _scrollbarTheme.thickness?.resolve(states)
           ?? _kScrollbarThicknessWithTrack;
       }
       // The default scrollbar thickness is smaller on mobile.
diff --git a/packages/flutter/test/material/scrollbar_theme_test.dart b/packages/flutter/test/material/scrollbar_theme_test.dart
index 635fa6fb2f5..642cab7aa68 100644
--- a/packages/flutter/test/material/scrollbar_theme_test.dart
+++ b/packages/flutter/test/material/scrollbar_theme_test.dart
@@ -362,6 +362,7 @@ void main() {
 
   testWidgets('Scrollbar widget properties take priority over theme', (WidgetTester tester) async {
     const double thickness = 4.0;
+    const double edgeMargin = 2.0;
     const bool showTrackOnHover = true;
     const Radius radius = Radius.circular(3.0);
     final ScrollController scrollController = ScrollController();
@@ -394,14 +395,14 @@ void main() {
       find.byType(Scrollbar),
       paints..rrect(
         rrect: RRect.fromRectAndRadius(
-          const Rect.fromLTRB(794.0, 0.0, 798.0, 90.0),
+          const Rect.fromLTRB(800 - thickness - edgeMargin, 0.0, 798.0, 90.0),
           const Radius.circular(3.0),
         ),
         color: _kDefaultIdleThumbColor,
       ),
     );
 
-    // Drag scrollbar behavior
+    // Drag scrollbar behavior.
     const double scrollAmount = 10.0;
     final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(797.0, 45.0));
     await tester.pumpAndSettle();
@@ -410,7 +411,7 @@ void main() {
       find.byType(Scrollbar),
       paints..rrect(
         rrect: RRect.fromRectAndRadius(
-          const Rect.fromLTRB(794.0, 0.0, 798.0, 90.0),
+          const Rect.fromLTRB(800 - thickness - edgeMargin, 0.0, 798.0, 90.0),
           const Radius.circular(3.0),
         ),
         // Drag color
@@ -423,7 +424,7 @@ void main() {
     await dragScrollbarGesture.up();
     await tester.pumpAndSettle();
 
-    // Hover scrollbar behavior
+    // Hover scrollbar behavior.
     final TestGesture gesture = await tester.createGesture(kind: ui.PointerDeviceKind.mouse);
     await gesture.addPointer();
     await gesture.moveTo(const Offset(794.0, 5.0));
@@ -433,18 +434,18 @@ void main() {
       find.byType(Scrollbar),
       paints
         ..rect(
-          rect: const Rect.fromLTRB(784.0, 0.0, 800.0, 600.0),
+          rect: const Rect.fromLTRB(792.0, 0.0, 800.0, 600.0),
           color: const Color(0x08000000),
         )
         ..line(
-          p1: const Offset(784.0, 0.0),
-          p2: const Offset(784.0, 600.0),
+          p1: const Offset(792.0, 0.0),
+          p2: const Offset(792.0, 600.0),
           strokeWidth: 1.0,
           color: const Color(0x1a000000),
         )
         ..rrect(
           rrect: RRect.fromRectAndRadius(
-            const Rect.fromLTRB(786.0, 10.0, 798.0, 100.0),
+            const Rect.fromLTRB(800 - thickness - edgeMargin, 10.0, 798.0, 100.0),
             const Radius.circular(3.0),
           ),
           // Hover color