diff --git a/lcl/forms.pp b/lcl/forms.pp
index 8d425f5ec3..e0685c3608 100644
--- a/lcl/forms.pp
+++ b/lcl/forms.pp
@@ -166,6 +166,7 @@ type
     procedure WMSize(var Message: TLMSize); message LM_Size;
     procedure WMHScroll(var Message : TLMHScroll); message LM_HScroll;
     procedure WMVScroll(var Message : TLMVScroll); message LM_VScroll;
+    procedure WMMouseWheel(var Message: TLMMouseEvent); message LM_MOUSEWHEEL;
     procedure ComputeScrollbars; virtual;
     procedure SetAutoScroll(Value: Boolean); virtual;
     procedure Loaded; override;
diff --git a/lcl/include/scrollingwincontrol.inc b/lcl/include/scrollingwincontrol.inc
index e3b98536b4..fe0070b0a2 100644
--- a/lcl/include/scrollingwincontrol.inc
+++ b/lcl/include/scrollingwincontrol.inc
@@ -304,6 +304,18 @@ begin
   HorzScrollbar.ScrollHandler(Message);
 end;
 
+procedure TScrollingWinControl.WMMouseWheel(var Message: TLMMouseEvent);
+begin
+  // support VertScrollBar.Increment on Windows.
+  // The code has no meaning on other OS because scrolling is handled there directly by the OS
+  if Mouse.WheelScrollLines > 0 then
+    Message.WheelDelta :=
+      (Min(High(Message.WheelDelta), Max(Low(Message.WheelDelta),
+        (VertScrollBar.Increment * Message.WheelDelta))) div 120) * 120;
+
+  inherited WMMouseWheel(Message);
+end;
+
 constructor TScrollingWinControl.Create(TheOwner : TComponent);
 begin
   Inherited Create(TheOwner);