<ListBox x:Name="imageListBox" ScrollViewer.HorizontalScrollBarVisibility="Visible" ScrollViewer.VerticalScrollBarVisibility = "Disabled" IsSynchronizedWithCurrentItem="False">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBoxItem>first</ListBoxItem>
<ListBoxItem>second</ListBoxItem>
</ListBox>
This should work for you!