diff --git a/lcl/interfaces/qt5/qtwsstdctrls.pp b/lcl/interfaces/qt5/qtwsstdctrls.pp
index a1c6a1e3b4..040526d461 100644
--- a/lcl/interfaces/qt5/qtwsstdctrls.pp
+++ b/lcl/interfaces/qt5/qtwsstdctrls.pp
@@ -580,8 +580,17 @@ end;
   Returns: Nothing
  ------------------------------------------------------------------------------}
 class function TQtWSCustomListBox.GetTopIndex(const ACustomListBox: TCustomListBox): integer;
+var
+  QtListWidget: TQtListWidget;
+  AQtPoint: TQtPoint;
 begin
   Result := 0;
+  if not WSCheckHandleAllocated(ACustomListBox, 'GetTopIndex') then
+    Exit;
+  QtListWidget := TQtListWidget(ACustomListBox.Handle);
+  AQtPoint.x := 0;
+  AQtPoint.y := 0;
+  Result := QtListWidget.IndexAt(@AQtPoint);
 end;
 
 {------------------------------------------------------------------------------
diff --git a/lcl/interfaces/qt6/qtwsstdctrls.pp b/lcl/interfaces/qt6/qtwsstdctrls.pp
index 9aec958dd1..7c2a59806a 100644
--- a/lcl/interfaces/qt6/qtwsstdctrls.pp
+++ b/lcl/interfaces/qt6/qtwsstdctrls.pp
@@ -580,8 +580,17 @@ end;
   Returns: Nothing
  ------------------------------------------------------------------------------}
 class function TQtWSCustomListBox.GetTopIndex(const ACustomListBox: TCustomListBox): integer;
+var
+  QtListWidget: TQtListWidget;
+  AQtPoint: TQtPoint;
 begin
   Result := 0;
+  if not WSCheckHandleAllocated(ACustomListBox, 'GetTopIndex') then
+    Exit;
+  QtListWidget := TQtListWidget(ACustomListBox.Handle);
+  AQtPoint.x := 0;
+  AQtPoint.y := 0;
+  Result := QtListWidget.IndexAt(@AQtPoint);
 end;
 
 {------------------------------------------------------------------------------