diff --git a/src/Semi.Avalonia/Controls/Calendar.axaml b/src/Semi.Avalonia/Controls/Calendar.axaml
index 9189a7c..d8552b3 100644
--- a/src/Semi.Avalonia/Controls/Calendar.axaml
+++ b/src/Semi.Avalonia/Controls/Calendar.axaml
@@ -38,6 +38,7 @@
                     VerticalAlignment="Center"
                     x:DataType="x:String"
                     FontSize="12"
+                    FontWeight="{DynamicResource CalendarItemWeekDayNameFontWeight}"
                     Foreground="{DynamicResource CalendarItemWeekDayNameForeground}"
                     Text="{Binding}" />
             </Template>
diff --git a/src/Semi.Avalonia/Themes/Shared/Calendar.axaml b/src/Semi.Avalonia/Themes/Shared/Calendar.axaml
index 47d4f95..bdbe626 100644
--- a/src/Semi.Avalonia/Themes/Shared/Calendar.axaml
+++ b/src/Semi.Avalonia/Themes/Shared/Calendar.axaml
@@ -2,6 +2,7 @@
     <StaticResource x:Key="CalendarBorderThickness" ResourceKey="SemiBorderThicknessControl" />
     <StaticResource x:Key="CalendarCornerRadius" ResourceKey="SemiBorderRadiusMedium" />
     <GridLength x:Key="CalendarItemWeekDayNameHeight">40</GridLength>
+    <StaticResource x:Key="CalendarItemWeekDayNameFontWeight" ResourceKey="SemiFontWeightBold" />
     <StaticResource x:Key="CalendarItemPreviousIconGlyph" ResourceKey="SemiIconChevronLeft" />
     <StaticResource x:Key="CalendarItemNextIconGlyph" ResourceKey="SemiIconChevronRight" />
     <StaticResource x:Key="CalendarItemCalendarButtonSelectedFontWeight" ResourceKey="SemiFontWeightBold" />