diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index ca516c8918..e4642c1453 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -516,7 +516,9 @@
                   BorderBrush="{TemplateBinding BorderBrush}"
                   BorderThickness="{TemplateBinding BorderThickness}"
                   CornerRadius="{TemplateBinding CornerRadius}">
-            <Grid ColumnDefinitions="Auto,*,Auto" RowDefinitions="Auto,*,Auto,Auto">
+            <Grid ColumnDefinitions="Auto,*,Auto" 
+                  RowDefinitions="Auto,*,Auto,Auto"
+                  ClipToBounds="True">
               <DataGridColumnHeader Name="PART_TopLeftCornerHeader"
                                     Theme="{StaticResource DataGridTopLeftColumnHeader}" />
               <DataGridColumnHeadersPresenter Name="PART_ColumnHeadersPresenter"
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Simple.xaml b/src/Avalonia.Controls.DataGrid/Themes/Simple.xaml
index 464a12770e..36e648db6b 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Simple.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Simple.xaml
@@ -319,7 +319,8 @@
                   BorderThickness="{TemplateBinding BorderThickness}"
                   CornerRadius="{TemplateBinding CornerRadius}">
             <Grid ColumnDefinitions="Auto,*,Auto"
-                  RowDefinitions="Auto,*,Auto,Auto">
+                  RowDefinitions="Auto,*,Auto,Auto"
+                  ClipToBounds="True">
               <DataGridColumnHeader Name="PART_TopLeftCornerHeader"
                                     Width="22" />
               <DataGridColumnHeadersPresenter Name="PART_ColumnHeadersPresenter"