diff --git a/packages/flutter/lib/src/material/popup_menu.dart b/packages/flutter/lib/src/material/popup_menu.dart
index 3e9a3a17685..0159e40adb5 100644
--- a/packages/flutter/lib/src/material/popup_menu.dart
+++ b/packages/flutter/lib/src/material/popup_menu.dart
@@ -715,23 +715,12 @@ class _PopupMenuRouteLayout extends SingleChildLayoutDelegate {
 
   @override
   Offset getPositionForChild(Size size, Size childSize) {
+    final double y = position.top;
+
+    // Find the ideal horizontal position.
     // size: The size of the overlay.
     // childSize: The size of the menu, when fully open, as determined by
     // getConstraintsForChild.
-
-    final double buttonHeight = size.height - position.top - position.bottom;
-    // Find the ideal vertical position.
-    double y = position.top;
-    if (selectedItemIndex != null) {
-      double selectedItemOffset = _kMenuVerticalPadding;
-      for (int index = 0; index < selectedItemIndex!; index += 1) {
-        selectedItemOffset += itemSizes[index]!.height;
-      }
-      selectedItemOffset += itemSizes[selectedItemIndex!]!.height / 2;
-      y = y + buttonHeight / 2.0 - selectedItemOffset;
-    }
-
-    // Find the ideal horizontal position.
     double x;
     if (position.left > position.right) {
       // Menu button is closer to the right edge, so grow to the left, aligned to the right edge.
diff --git a/packages/flutter/test/material/popup_menu_test.dart b/packages/flutter/test/material/popup_menu_test.dart
index e462834c917..e8ed919b920 100644
--- a/packages/flutter/test/material/popup_menu_test.dart
+++ b/packages/flutter/test/material/popup_menu_test.dart
@@ -3955,6 +3955,80 @@ void main() {
 
     expect(tester.getSize(find.byType(Material).last), within(distance: 0.1, from: const Size(112.0, 160.0)));
   });
+
+  testWidgets('PopupMenuButton properly positions a constrained-size popup', (WidgetTester tester) async {
+    final Size windowSize = tester.view.physicalSize / tester.view.devicePixelRatio;
+    const int length = 50;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Padding(
+            padding: const EdgeInsets.all(50),
+            child: Align(
+              alignment: Alignment.bottomCenter,
+              child: PopupMenuButton<int>(
+                itemBuilder: (BuildContext context) {
+                  return List<PopupMenuEntry<int>>.generate(length, (int index) {
+                    return PopupMenuItem<int>(value: index, child: Text('item #$index'));
+                  });
+                },
+                constraints: BoxConstraints(maxHeight: windowSize.height / 3),
+                popUpAnimationStyle: AnimationStyle.noAnimation,
+                initialValue: length - 1,
+                child: const Text('click here'),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+    await tester.tap(find.text('click here'));
+    await tester.pump();
+
+    // Set up finders and verify basic widget structure
+    final Finder findButton = find.byType(PopupMenuButton<int>);
+    final Finder findLastItem = find.text('item #49');
+    final Finder findListBody = find.byType(ListBody);
+    final Finder findListViewport = find.ancestor(
+      of: findListBody,
+      matching: find.byType(SingleChildScrollView),
+    );
+    expect(findButton, findsOne);
+    expect(findLastItem, findsOne);
+    expect(findListBody, findsOne);
+    expect(findListViewport, findsOne);
+
+    // The button and the list viewport should overlap
+    final RenderBox button = tester.renderObject<RenderBox>(findButton);
+    final Rect buttonBounds = button.localToGlobal(Offset.zero) & button.size;
+    final RenderBox listViewport = tester.renderObject<RenderBox>(findListViewport);
+    final Rect listViewportBounds = listViewport.localToGlobal(Offset.zero) & listViewport.size;
+    expect(listViewportBounds.topLeft.dy, lessThanOrEqualTo(windowSize.height));
+    expect(listViewportBounds.bottomRight.dy, lessThanOrEqualTo(windowSize.height));
+    expect(listViewportBounds, overlaps(buttonBounds));
+  });
+}
+
+Matcher overlaps(Rect other) => OverlapsMatcher(other);
+
+class OverlapsMatcher extends Matcher {
+  OverlapsMatcher(this.other);
+
+  final Rect other;
+
+  @override
+  Description describe(Description description) {
+    return description.add('<Rect that overlaps with $other>');
+  }
+
+  @override
+  bool matches(Object? item, Map<dynamic, dynamic> matchState) => item is Rect && item.overlaps(other);
+
+  @override
+  Description describeMismatch(dynamic item, Description mismatchDescription,
+      Map<dynamic, dynamic> matchState, bool verbose) {
+    return mismatchDescription.add('does not overlap');
+  }
 }
 
 class TestApp extends StatelessWidget {