diff --git a/ICSharpCode.Decompiler/Output/ITextOutput.cs b/ICSharpCode.Decompiler/Output/ITextOutput.cs
index 9c5ac0548..8187f182f 100644
--- a/ICSharpCode.Decompiler/Output/ITextOutput.cs
+++ b/ICSharpCode.Decompiler/Output/ITextOutput.cs
@@ -26,6 +26,7 @@ namespace ICSharpCode.Decompiler
 {
 	public interface ITextOutput
 	{
+		string IndentationString { get; set; }
 		void Indent();
 		void Unindent();
 		void Write(char ch);
diff --git a/ICSharpCode.Decompiler/Output/PlainTextOutput.cs b/ICSharpCode.Decompiler/Output/PlainTextOutput.cs
index a2fcafa1b..14f4e4903 100644
--- a/ICSharpCode.Decompiler/Output/PlainTextOutput.cs
+++ b/ICSharpCode.Decompiler/Output/PlainTextOutput.cs
@@ -35,7 +35,9 @@ namespace ICSharpCode.Decompiler
 		
 		int line = 1;
 		int column = 1;
-		
+
+		public string IndentationString { get; set; } = "\t";
+
 		public PlainTextOutput(TextWriter writer)
 		{
 			if (writer == null)
@@ -74,7 +76,7 @@ namespace ICSharpCode.Decompiler
 			if (needsIndent) {
 				needsIndent = false;
 				for (int i = 0; i < indent; i++) {
-					writer.Write('\t');
+					writer.Write(IndentationString);
 				}
 				column += indent;
 			}
@@ -154,6 +156,15 @@ namespace ICSharpCode.Decompiler
 			this.actions = new List<Action<ITextOutput>>();
 		}
 
+		string ITextOutput.IndentationString {
+			get {
+				return target.IndentationString;
+			}
+			set {
+				target.IndentationString = value;
+			}
+		}
+
 		public void Commit()
 		{
 			foreach (var action in actions) {
diff --git a/ILSpy/DecompilationOptions.cs b/ILSpy/DecompilationOptions.cs
index 229e876b0..736ec2eb0 100644
--- a/ILSpy/DecompilationOptions.cs
+++ b/ILSpy/DecompilationOptions.cs
@@ -86,6 +86,17 @@ namespace ICSharpCode.ILSpy
 			newSettings.ExpandUsingDeclarations = displaySettings.ExpandUsingDeclarations;
 			newSettings.FoldBraces = displaySettings.FoldBraces;
 			newSettings.ShowDebugInfo = displaySettings.ShowDebugInfo;
+			newSettings.CSharpFormattingOptions.IndentationString = GetIndentationString(displaySettings);
+		}
+
+		private string GetIndentationString(DisplaySettings displaySettings)
+		{
+			if (displaySettings.IndentationUseTabs) {
+				int numberOfTabs = displaySettings.IndentationSize / displaySettings.IndentationTabSize;
+				int numberOfSpaces = displaySettings.IndentationSize % displaySettings.IndentationTabSize;
+				return new string('\t', numberOfTabs) + new string(' ', numberOfSpaces);
+			}
+			return new string(' ', displaySettings.IndentationSize);
 		}
 	}
 }
diff --git a/ILSpy/Languages/CSharpILMixedLanguage.cs b/ILSpy/Languages/CSharpILMixedLanguage.cs
index 855dd8b99..8b4858c75 100644
--- a/ILSpy/Languages/CSharpILMixedLanguage.cs
+++ b/ILSpy/Languages/CSharpILMixedLanguage.cs
@@ -65,7 +65,7 @@ namespace ICSharpCode.ILSpy
 		static void WriteCode(TextWriter output, DecompilerSettings settings, SyntaxTree syntaxTree, IDecompilerTypeSystem typeSystem)
 		{
 			syntaxTree.AcceptVisitor(new InsertParenthesesVisitor { InsertParenthesesForReadability = true });
-			TokenWriter tokenWriter = new TextWriterTokenWriter(output);
+			TokenWriter tokenWriter = new TextWriterTokenWriter(output) { IndentationString = settings.CSharpFormattingOptions.IndentationString };
 			tokenWriter = TokenWriter.WrapInWriterThatSetsLocationsInAST(tokenWriter);
 			syntaxTree.AcceptVisitor(new CSharpOutputVisitor(tokenWriter, settings.CSharpFormattingOptions));
 		}
diff --git a/ILSpy/Languages/CSharpLanguage.cs b/ILSpy/Languages/CSharpLanguage.cs
index 25b09f4f4..1d34d068b 100644
--- a/ILSpy/Languages/CSharpLanguage.cs
+++ b/ILSpy/Languages/CSharpLanguage.cs
@@ -121,6 +121,7 @@ namespace ICSharpCode.ILSpy
 		void WriteCode(ITextOutput output, DecompilerSettings settings, SyntaxTree syntaxTree, IDecompilerTypeSystem typeSystem)
 		{
 			syntaxTree.AcceptVisitor(new InsertParenthesesVisitor { InsertParenthesesForReadability = true });
+			output.IndentationString = settings.CSharpFormattingOptions.IndentationString;
 			TokenWriter tokenWriter = new TextTokenWriter(output, settings, typeSystem);
 			if (output is ISmartTextOutput highlightingOutput) {
 				tokenWriter = new CSharpHighlightingTokenWriter(tokenWriter, highlightingOutput);
diff --git a/ILSpy/Languages/ILLanguage.cs b/ILSpy/Languages/ILLanguage.cs
index 137548652..e2ab9d1f3 100644
--- a/ILSpy/Languages/ILLanguage.cs
+++ b/ILSpy/Languages/ILLanguage.cs
@@ -52,6 +52,7 @@ namespace ICSharpCode.ILSpy
 		
 		protected virtual ReflectionDisassembler CreateDisassembler(ITextOutput output, DecompilationOptions options)
 		{
+			output.IndentationString = options.DecompilerSettings.CSharpFormattingOptions.IndentationString;
 			return new ReflectionDisassembler(output, options.CancellationToken) {
 				DetectControlStructure = detectControlStructure,
 				ShowSequencePoints = options.DecompilerSettings.ShowDebugInfo,
diff --git a/ILSpy/Options/DecompilerSettingsPanel.xaml b/ILSpy/Options/DecompilerSettingsPanel.xaml
index d3f996603..c020084e3 100644
--- a/ILSpy/Options/DecompilerSettingsPanel.xaml
+++ b/ILSpy/Options/DecompilerSettingsPanel.xaml
@@ -18,7 +18,7 @@
 		<Grid.ColumnDefinitions>
 			<ColumnDefinition Width="*" />
 		</Grid.ColumnDefinitions>
-		<TextBlock Margin="3" Grid.ColumnSpan="3" TextWrapping="Wrap" Text="The settings selected below are applied to the decompiler output in addition to the setting selected in the language drop-down. Note that some settings implicitly depend on each other, e.g.: LINQ expressions cannot be introduced without first transforming static calls to extension method calls." />
+		<TextBlock Margin="3" Grid.ColumnSpan="3" TextWrapping="Wrap" Text="The settings selected below are applied to the decompiler output in combination with the selection in the language drop-down. Selecting a lower language version in the drop-down will deactivate all selected options of the higher versions. Note that some settings implicitly depend on each other, e.g.: LINQ expressions cannot be introduced without first transforming static calls to extension method calls." />
 		<ListBox Grid.Row="1" ItemsSource="{Binding Source={StaticResource SettingsCollection}}">
 			<ListBox.ItemContainerStyle>
 				<Style TargetType="ListBoxItem">
diff --git a/ILSpy/Options/DisplaySettings.cs b/ILSpy/Options/DisplaySettings.cs
index e432c7238..3d6053961 100644
--- a/ILSpy/Options/DisplaySettings.cs
+++ b/ILSpy/Options/DisplaySettings.cs
@@ -179,6 +179,42 @@ namespace ICSharpCode.ILSpy.Options
 			}
 		}
 
+		bool indentationUseTabs = true;
+
+		public bool IndentationUseTabs {
+			get { return indentationUseTabs; }
+			set {
+				if (indentationUseTabs != value) {
+					indentationUseTabs = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
+		int indentationTabSize = 4;
+
+		public int IndentationTabSize {
+			get { return indentationTabSize; }
+			set {
+				if (indentationTabSize != value) {
+					indentationTabSize = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
+		int indentationSize = 4;
+
+		public int IndentationSize {
+			get { return indentationSize; }
+			set {
+				if (indentationSize != value) {
+					indentationSize = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		public void CopyValues(DisplaySettings s)
 		{
 			this.SelectedFont = s.selectedFont;
@@ -192,6 +228,9 @@ namespace ICSharpCode.ILSpy.Options
 			this.FoldBraces = s.foldBraces;
 			this.ExpandMemberDefinitions = s.expandMemberDefinitions;
 			this.ExpandUsingDeclarations = s.expandUsingDeclarations;
+			this.IndentationUseTabs = s.indentationUseTabs;
+			this.IndentationTabSize = s.indentationTabSize;
+			this.IndentationSize = s.indentationSize;
 		}
 	}
 }
diff --git a/ILSpy/Options/DisplaySettingsPanel.xaml b/ILSpy/Options/DisplaySettingsPanel.xaml
index 49e54fb7e..5fb2e4610 100644
--- a/ILSpy/Options/DisplaySettingsPanel.xaml
+++ b/ILSpy/Options/DisplaySettingsPanel.xaml
@@ -7,6 +7,7 @@
 	</UserControl.Resources>
 	<Grid>
 		<Grid.RowDefinitions>
+			<RowDefinition Height="Auto"/>
 			<RowDefinition Height="Auto"/>
 			<RowDefinition/>
 		</Grid.RowDefinitions>
@@ -57,7 +58,20 @@
 				</Border>
 			</Grid>
 		</GroupBox>
-		<GroupBox Header="Other options" Grid.Row="1">
+		<GroupBox Header="Indentation" Grid.Row="1">
+			<StackPanel Margin="3">
+				<CheckBox IsChecked="{Binding IndentationUseTabs}">Use tabs instead of spaces</CheckBox>
+				<StackPanel Orientation="Horizontal">
+					<Label>Tab size:</Label>
+					<TextBox x:Name="tabSizeTextBox" Width="50" Margin="3" Text="{Binding IndentationTabSize}" PreviewTextInput="TextBox_PreviewTextInput" />
+				</StackPanel>
+				<StackPanel Orientation="Horizontal">
+					<Label>Indent size:</Label>
+					<TextBox x:Name="indentSizeTextBox" Width="50" Margin="3" Text="{Binding IndentationSize}" PreviewTextInput="TextBox_PreviewTextInput" />
+				</StackPanel>
+			</StackPanel>
+		</GroupBox>
+		<GroupBox Header="Other options" Grid.Row="2">
 			<StackPanel Margin="3">
 				<CheckBox IsChecked="{Binding ShowLineNumbers}">Show line numbers</CheckBox>
 				<CheckBox IsChecked="{Binding ShowMetadataTokens}">Show metadata tokens</CheckBox>
diff --git a/ILSpy/Options/DisplaySettingsPanel.xaml.cs b/ILSpy/Options/DisplaySettingsPanel.xaml.cs
index 07fa5bd78..91055a940 100644
--- a/ILSpy/Options/DisplaySettingsPanel.xaml.cs
+++ b/ILSpy/Options/DisplaySettingsPanel.xaml.cs
@@ -37,7 +37,10 @@ namespace ICSharpCode.ILSpy.Options
 		public DisplaySettingsPanel()
 		{
 			InitializeComponent();
-			
+
+			DataObject.AddPastingHandler(tabSizeTextBox, OnPaste);
+			DataObject.AddPastingHandler(indentSizeTextBox, OnPaste);
+
 			Task<FontFamily[]> task = new Task<FontFamily[]>(FontLoader);
 			task.Start();
 			task.ContinueWith(
@@ -57,7 +60,7 @@ namespace ICSharpCode.ILSpy.Options
 				}
 			);
 		}
-		
+
 		public void Load(ILSpySettings settings)
 		{
 			this.DataContext = LoadDisplaySettings(settings);
@@ -108,6 +111,9 @@ namespace ICSharpCode.ILSpy.Options
 			s.FoldBraces = (bool?)e.Attribute("FoldBraces") ?? false;
 			s.ExpandMemberDefinitions = (bool?)e.Attribute("ExpandMemberDefinitions") ?? false;
 			s.ExpandUsingDeclarations = (bool?)e.Attribute("ExpandUsingDeclarations") ?? false;
+			s.IndentationUseTabs = (bool?)e.Attribute("IndentationUseTabs") ?? true;
+			s.IndentationSize = (int?)e.Attribute("IndentationSize") ?? 4;
+			s.IndentationTabSize = (int?)e.Attribute("IndentationTabSize") ?? 4;
 
 			return s;
 		}
@@ -127,7 +133,9 @@ namespace ICSharpCode.ILSpy.Options
 			section.SetAttributeValue("SortResults", s.SortResults);
 			section.SetAttributeValue("FoldBraces", s.FoldBraces);
 			section.SetAttributeValue("ExpandMemberDefinitions", s.ExpandMemberDefinitions);
-			section.SetAttributeValue("ExpandUsingDeclarations", s.ExpandUsingDeclarations);
+			section.SetAttributeValue("IndentationUseTabs", s.IndentationUseTabs);
+			section.SetAttributeValue("IndentationSize", s.IndentationSize);
+			section.SetAttributeValue("IndentationTabSize", s.IndentationTabSize);
 
 			XElement existingElement = root.Element("DisplaySettings");
 			if (existingElement != null)
@@ -138,8 +146,23 @@ namespace ICSharpCode.ILSpy.Options
 			if (currentDisplaySettings != null)
 				currentDisplaySettings.CopyValues(s);
 		}
+
+		private void TextBox_PreviewTextInput(object sender, System.Windows.Input.TextCompositionEventArgs e)
+		{
+			if (!e.Text.All(char.IsDigit))
+				e.Handled = true;
+		}
+
+		private void OnPaste(object sender, DataObjectPastingEventArgs e)
+		{
+			if (!e.SourceDataObject.GetDataPresent(DataFormats.UnicodeText, true))
+				return;
+			var text = (string)e.SourceDataObject.GetData(DataFormats.UnicodeText, true) ?? string.Empty;
+			if (!text.All(char.IsDigit))
+				e.CancelCommand();
+		}
 	}
-	
+
 	public class FontSizeConverter : IValueConverter
 	{
 		public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)