diff --git a/packages/flutter/lib/src/cupertino/text_selection_toolbar.dart b/packages/flutter/lib/src/cupertino/text_selection_toolbar.dart
index 6e89fc6dd5d..0bd6f1db7b0 100644
--- a/packages/flutter/lib/src/cupertino/text_selection_toolbar.dart
+++ b/packages/flutter/lib/src/cupertino/text_selection_toolbar.dart
@@ -1008,7 +1008,6 @@ class _RenderCupertinoTextSelectionToolbarItems extends RenderBox with Container
     final double subsequentPageButtonsWidth = _backButton!.size.width + _nextButton!.size.width;
     double currentButtonPosition = 0.0;
     late double toolbarWidth; // The width of the whole widget.
-    late double firstPageWidth;
     int currentPage = 0;
     int i = -1;
     visitChildren((RenderObject renderObjectChild) {
@@ -1031,7 +1030,7 @@ class _RenderCupertinoTextSelectionToolbarItems extends RenderBox with Container
       // The width of the menu is set by the first page.
       child.layout(
         BoxConstraints(
-          maxWidth: (currentPage == 0 ? constraints.maxWidth : firstPageWidth) - paginationButtonsWidth,
+          maxWidth: constraints.maxWidth - paginationButtonsWidth,
           minHeight: greatestHeight,
           maxHeight: greatestHeight,
         ),
@@ -1047,7 +1046,7 @@ class _RenderCupertinoTextSelectionToolbarItems extends RenderBox with Container
         paginationButtonsWidth = _backButton!.size.width + _nextButton!.size.width;
         child.layout(
           BoxConstraints(
-            maxWidth: firstPageWidth - paginationButtonsWidth,
+            maxWidth: constraints.maxWidth - paginationButtonsWidth,
             minHeight: greatestHeight,
             maxHeight: greatestHeight,
           ),
@@ -1058,9 +1057,6 @@ class _RenderCupertinoTextSelectionToolbarItems extends RenderBox with Container
       currentButtonPosition += child.size.width + dividerWidth;
       childParentData.shouldPaint = currentPage == page;
 
-      if (currentPage == 0) {
-        firstPageWidth = currentButtonPosition + _nextButton!.size.width;
-      }
       if (currentPage == page) {
         toolbarWidth = currentButtonPosition;
       }
diff --git a/packages/flutter/test/cupertino/text_selection_toolbar_test.dart b/packages/flutter/test/cupertino/text_selection_toolbar_test.dart
index 170d9d556e8..bf46a864b7c 100644
--- a/packages/flutter/test/cupertino/text_selection_toolbar_test.dart
+++ b/packages/flutter/test/cupertino/text_selection_toolbar_test.dart
@@ -273,6 +273,62 @@ void main() {
     expect(findOverflowBackButton(), findsNothing);
   }, skip: kIsWeb); // [intended] We do not use Flutter-rendered context menu on the Web.
 
+  testWidgets('correctly sizes large toolbar buttons', (WidgetTester tester) async {
+    final GlobalKey firstBoxKey = GlobalKey();
+    final GlobalKey secondBoxKey = GlobalKey();
+    final GlobalKey thirdBoxKey = GlobalKey();
+    final GlobalKey fourthBoxKey = GlobalKey();
+
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: Center(
+          child: SizedBox(
+            width: 420,
+            child: CupertinoTextSelectionToolbar(
+              anchorAbove: const Offset(50.0, 100.0),
+              anchorBelow: const Offset(50.0, 200.0),
+              children: <Widget>[
+                SizedBox(key: firstBoxKey, width: 100),
+                SizedBox(key: secondBoxKey, width: 300),
+                SizedBox(key: thirdBoxKey, width: 100),
+                SizedBox(key: fourthBoxKey, width: 100),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // The first page isn't wide enough to show the second button.
+    expect(find.byKey(firstBoxKey), findsOneWidget);
+    expect(find.byKey(secondBoxKey), findsNothing);
+    expect(find.byKey(thirdBoxKey), findsNothing);
+    expect(find.byKey(fourthBoxKey), findsNothing);
+
+    // Show the next page.
+    await tester.tapAt(tester.getCenter(findOverflowNextButton()));
+    await tester.pumpAndSettle();
+
+    // The second page should show only the second button.
+    expect(find.byKey(firstBoxKey), findsNothing);
+    expect(find.byKey(secondBoxKey), findsOneWidget);
+    expect(find.byKey(thirdBoxKey), findsNothing);
+    expect(find.byKey(fourthBoxKey), findsNothing);
+
+    // The button's width shouldn't be limited by the first page's width.
+    expect(tester.getSize(find.byKey(secondBoxKey)).width, 300);
+
+    // Show the next page.
+    await tester.tapAt(tester.getCenter(findOverflowNextButton()));
+    await tester.pumpAndSettle();
+
+    // The third page should show the last two items.
+    expect(find.byKey(firstBoxKey), findsNothing);
+    expect(find.byKey(secondBoxKey), findsNothing);
+    expect(find.byKey(thirdBoxKey), findsOneWidget);
+    expect(find.byKey(fourthBoxKey), findsOneWidget);
+  }, skip: kIsWeb); // [intended] We do not use Flutter-rendered context menu on the Web.
+
   testWidgets('positions itself at anchorAbove if it fits', (WidgetTester tester) async {
     late StateSetter setState;
     const double height = 50.0;