diff --git a/src/Shared/HandyControl_Shared/Controls/Attach/ExpanderElement.cs b/src/Shared/HandyControl_Shared/Controls/Attach/ExpanderElement.cs
new file mode 100644
index 00000000..05b76f1e
--- /dev/null
+++ b/src/Shared/HandyControl_Shared/Controls/Attach/ExpanderElement.cs
@@ -0,0 +1,37 @@
+using System.Windows;
+
+namespace HandyControl.Controls;
+
+/// <summary>
+/// Header text orientation of an <see cref="Expander"/> when <see cref="Expander.ExpandDirection"/> is Left or Right.
+/// </summary>
+public enum ExpanderHeaderTextOrientation
+{
+    /// <summary>
+    /// Same as the current behavior: the whole header is rotated -90 degrees (glyphs lying on their side).
+    /// </summary>
+    Default = 0,
+
+    /// <summary>
+    /// Upright vertical: characters stand upright and stack top-to-bottom.
+    /// </summary>
+    Vertical = 1,
+
+    /// <summary>
+    /// Upright horizontal: a single horizontal line.
+    /// </summary>
+    Horizontal = 2
+}
+
+/// <summary>
+/// Attached properties for <see cref="Expander"/>.
+/// </summary>
+public class ExpanderElement
+{
+    public static readonly DependencyProperty HeaderTextOrientationProperty = DependencyProperty.RegisterAttached(
+        "HeaderTextOrientation", typeof(ExpanderHeaderTextOrientation), typeof(ExpanderElement), new FrameworkPropertyMetadata(ExpanderHeaderTextOrientation.Default));
+
+    public static void SetHeaderTextOrientation(DependencyObject element, ExpanderHeaderTextOrientation value) => element.SetValue(HeaderTextOrientationProperty, value);
+
+    public static ExpanderHeaderTextOrientation GetHeaderTextOrientation(DependencyObject element) => (ExpanderHeaderTextOrientation) element.GetValue(HeaderTextOrientationProperty);
+}
diff --git a/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems b/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems
index 2f1732d9..47744c2e 100644
--- a/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems
+++ b/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems
@@ -15,6 +15,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\DataGridAttach.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\DropDownElement.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\EdgeElement.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\ExpanderElement.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\ComboBoxAttach.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\GridAttach.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Controls\Attach\GridViewAttach.cs" />
diff --git a/src/Shared/HandyControl_Shared/Themes/Styles/Base/ExpanderBaseStyle.xaml b/src/Shared/HandyControl_Shared/Themes/Styles/Base/ExpanderBaseStyle.xaml
index 8412b1f3..139f2ec2 100644
--- a/src/Shared/HandyControl_Shared/Themes/Styles/Base/ExpanderBaseStyle.xaml
+++ b/src/Shared/HandyControl_Shared/Themes/Styles/Base/ExpanderBaseStyle.xaml
@@ -19,7 +19,7 @@
                             <RotateTransform Angle="-90" />
                         </TransformGroup>
                     </Grid.LayoutTransform>
-                    <ContentPresenter ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
+                    <ContentPresenter Name="HeaderText" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
                     <Path Name="PathArrow" IsHitTestVisible="False" Grid.Column="1" Stretch="Uniform" Fill="{TemplateBinding Foreground}" Data="{StaticResource UpGeometry}" Width="12" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="Center" />
                 </Grid>
             </ToggleButton>
@@ -34,6 +34,27 @@
             <Trigger Property="IsEnabled" Value="false">
                 <Setter Property="Opacity" Value=".4" />
             </Trigger>
+            <Trigger Property="hc:ExpanderElement.HeaderTextOrientation" Value="Vertical">
+                <Setter TargetName="HeaderText" Property="LayoutTransform">
+                    <Setter.Value>
+                        <RotateTransform Angle="90" />
+                    </Setter.Value>
+                </Setter>
+                <Setter TargetName="HeaderText" Property="ContentTemplate">
+                    <Setter.Value>
+                        <DataTemplate>
+                            <TextBlock Text="{Binding}" TextWrapping="Wrap" TextAlignment="Center" Width="{Binding FontSize, RelativeSource={RelativeSource AncestorType=Expander}}" />
+                        </DataTemplate>
+                    </Setter.Value>
+                </Setter>
+            </Trigger>
+            <Trigger Property="hc:ExpanderElement.HeaderTextOrientation" Value="Horizontal">
+                <Setter TargetName="HeaderText" Property="LayoutTransform">
+                    <Setter.Value>
+                        <RotateTransform Angle="90" />
+                    </Setter.Value>
+                </Setter>
+            </Trigger>
         </ControlTemplate.Triggers>
     </ControlTemplate>
 
@@ -84,7 +105,7 @@
                             <RotateTransform Angle="-90" />
                         </TransformGroup>
                     </Grid.LayoutTransform>
-                    <ContentPresenter ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
+                    <ContentPresenter Name="HeaderText" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
                     <Path Name="PathArrow" IsHitTestVisible="False" Grid.Column="1" Stretch="Uniform" Fill="{TemplateBinding Foreground}" Data="{StaticResource DownGeometry}" Width="12" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="Center" />
                 </Grid>
             </ToggleButton>
@@ -99,6 +120,27 @@
             <Trigger Property="IsEnabled" Value="false">
                 <Setter Property="Opacity" Value=".4" />
             </Trigger>
+            <Trigger Property="hc:ExpanderElement.HeaderTextOrientation" Value="Vertical">
+                <Setter TargetName="HeaderText" Property="LayoutTransform">
+                    <Setter.Value>
+                        <RotateTransform Angle="90" />
+                    </Setter.Value>
+                </Setter>
+                <Setter TargetName="HeaderText" Property="ContentTemplate">
+                    <Setter.Value>
+                        <DataTemplate>
+                            <TextBlock Text="{Binding}" TextWrapping="Wrap" TextAlignment="Center" Width="{Binding FontSize, RelativeSource={RelativeSource AncestorType=Expander}}" />
+                        </DataTemplate>
+                    </Setter.Value>
+                </Setter>
+            </Trigger>
+            <Trigger Property="hc:ExpanderElement.HeaderTextOrientation" Value="Horizontal">
+                <Setter TargetName="HeaderText" Property="LayoutTransform">
+                    <Setter.Value>
+                        <RotateTransform Angle="90" />
+                    </Setter.Value>
+                </Setter>
+            </Trigger>
         </ControlTemplate.Triggers>
     </ControlTemplate>