diff --git a/lcl/interfaces/gtk/gtkdef.pp b/lcl/interfaces/gtk/gtkdef.pp
index 705d9de7c8..1a301c89ae 100644
--- a/lcl/interfaces/gtk/gtkdef.pp
+++ b/lcl/interfaces/gtk/gtkdef.pp
@@ -77,6 +77,7 @@ type
     lgsTreeView,      // for gtk2
     lgsToolBar,       // toolbar
     lgsToolButton,    // button placed on toolbar
+    lgsCalendar,      // button placed on toolbar
     // user defined
     lgsUserDefined
     );
@@ -107,6 +108,7 @@ const
     'treeview',
     'toolbar',
     'toolbutton',
+    'calendar',
     ''
     );
 
diff --git a/lcl/interfaces/gtk/gtkproc.inc b/lcl/interfaces/gtk/gtkproc.inc
index fc6ed96125..bd41273b6f 100644
--- a/lcl/interfaces/gtk/gtkproc.inc
+++ b/lcl/interfaces/gtk/gtkproc.inc
@@ -7935,6 +7935,12 @@ begin
         AddToStyleWindow:=true;
         StyleObject^.Widget := gtk_statusbar_new;
       end
+    else
+      If CompareText(WName,LazGtkStyleNames[lgsCalendar])=0 then begin
+        lgs:=lgsCalendar;
+        AddToStyleWindow:=true;
+        StyleObject^.Widget := gtk_calendar_new;
+      end
     else
       If CompareText(WName,LazGtkStyleNames[lgsList])=0 then begin
         lgs:=lgsList;
diff --git a/lcl/interfaces/gtk2/gtk2wscalendar.pp b/lcl/interfaces/gtk2/gtk2wscalendar.pp
index a567214c32..2be2a766dd 100644
--- a/lcl/interfaces/gtk2/gtk2wscalendar.pp
+++ b/lcl/interfaces/gtk2/gtk2wscalendar.pp
@@ -58,6 +58,9 @@ type
     class procedure SetDateTime(const ACalendar: TCustomCalendar; const ADateTime: TDateTime); override;
     class procedure SetDisplaySettings(const ACalendar: TCustomCalendar;
       const ADisplaySettings: TDisplaySettings); override;
+    class procedure GetPreferredSize(const AWinControl: TWinControl;
+                        var PreferredWidth, PreferredHeight: integer;
+                        WithThemeSpace: Boolean); override;
   end;
 
 
@@ -292,4 +295,12 @@ begin
   gtk_Calendar_Display_options(GetCalendar(ACalendar), gtkCalendarDisplayOptions);
 end;
 
+class procedure TGtk2WSCustomCalendar.GetPreferredSize(
+  const AWinControl: TWinControl; var PreferredWidth, PreferredHeight: integer;
+  WithThemeSpace: Boolean);
+begin
+  GetGTKDefaultWidgetSize(AWinControl, PreferredWidth, PreferredHeight,
+                          WithThemeSpace);
+end;
+
 end.