diff --git a/src/Avalonia.Visuals/Media/BrushExtensions.cs b/src/Avalonia.Visuals/Media/BrushExtensions.cs
index 081029e205..265337476a 100644
--- a/src/Avalonia.Visuals/Media/BrushExtensions.cs
+++ b/src/Avalonia.Visuals/Media/BrushExtensions.cs
@@ -24,12 +24,27 @@ namespace Avalonia.Media
         }
 
         /// <summary>
-        /// Converts a pen to a pen with an immutable brush
+        /// Converts a dash style to an immutable dash style.
+        /// </summary>
+        /// <param name="style">The dash style.</param>
+        /// <returns>
+        /// The result of calling <see cref="DashStyle.ToImmutable"/> if the style is mutable,
+        /// otherwise <paramref name="style"/>.
+        /// </returns>
+        public static ImmutableDashStyle ToImmutable(this IDashStyle style)
+        {
+            Contract.Requires<ArgumentNullException>(style != null);
+
+            return style as ImmutableDashStyle ?? ((DashStyle)style).ToImmutable();
+        }
+
+        /// <summary>
+        /// Converts a pen to an immutable pen.
         /// </summary>
         /// <param name="pen">The pen.</param>
         /// <returns>
-        /// A copy of the pen with an immutable brush, or <paramref name="pen"/> if the pen's brush
-        /// is already immutable or null.
+        /// The result of calling <see cref="Pen.ToImmutable"/> if the brush is mutable,
+        /// otherwise <paramref name="pen"/>.
         /// </returns>
         public static ImmutablePen ToImmutable(this IPen pen)
         {
diff --git a/src/Avalonia.Visuals/Media/DashStyle.cs b/src/Avalonia.Visuals/Media/DashStyle.cs
index 9f03a0bd85..7784c73736 100644
--- a/src/Avalonia.Visuals/Media/DashStyle.cs
+++ b/src/Avalonia.Visuals/Media/DashStyle.cs
@@ -1,72 +1,114 @@
 namespace Avalonia.Media
 {
+    using System;
     using System.Collections.Generic;
+    using System.Linq;
     using Avalonia.Animation;
+    using Avalonia.Media.Immutable;
 
-    public class DashStyle : Animatable
+    /// <summary>
+    /// Represents the sequence of dashes and gaps that will be applied by a <see cref="Pen"/>.
+    /// </summary>
+    public class DashStyle : Animatable, IDashStyle, IAffectsRender
     {
-        private static DashStyle dash;
-        public static DashStyle Dash
-        {
-            get
-            {
-                if (dash == null)
-                {
-                    dash = new DashStyle(new double[] { 2, 2 }, 1);
-                }
-
-                return dash;
-            }
-        }
+        /// <summary>
+        /// Defines the <see cref="Dashes"/> property.
+        /// </summary>
+        public static readonly AvaloniaProperty<IReadOnlyList<double>> DashesProperty =
+            AvaloniaProperty.Register<DashStyle, IReadOnlyList<double>>(nameof(Dashes));
 
+        /// <summary>
+        /// Defines the <see cref="Offset"/> property.
+        /// </summary>
+        public static readonly AvaloniaProperty<double> OffsetProperty =
+            AvaloniaProperty.Register<DashStyle, double>(nameof(Offset));
 
+        private static ImmutableDashStyle s_dash;
+        private static ImmutableDashStyle s_dot;
+        private static ImmutableDashStyle s_dashDot;
+        private static ImmutableDashStyle s_dashDotDot;
 
-        private static DashStyle dot;
-        public static DashStyle Dot
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DashStyle"/> class.
+        /// </summary>
+        public DashStyle()
+            : this(null, 0)
         {
-            get { return dot ?? (dot = new DashStyle(new double[] {0, 2}, 0)); }
         }
 
-        private static DashStyle dashDot;
-        public static DashStyle DashDot
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DashStyle"/> class.
+        /// </summary>
+        /// <param name="dashes">The dashes collection.</param>
+        /// <param name="offset">The dash sequence offset.</param>
+        public DashStyle(IEnumerable<double> dashes, double offset)
         {
-            get
-            {
-                if (dashDot == null)
-                {
-                    dashDot = new DashStyle(new double[] { 2, 2, 0, 2 }, 1);
-                }
-
-                return dashDot;
-            }
+            Dashes = (IReadOnlyList<double>)dashes?.ToList() ?? Array.Empty<double>();
+            Offset = offset;
         }
 
-        private static DashStyle dashDotDot;
-        public static DashStyle DashDotDot
+        static DashStyle()
         {
-            get
+            void RaiseInvalidated(AvaloniaPropertyChangedEventArgs e)
             {
-                if (dashDotDot == null)
-                {
-                    dashDotDot = new DashStyle(new double[] { 2, 2, 0, 2, 0, 2 }, 1);
-                }
-
-                return dashDotDot;
+                ((DashStyle)e.Sender).Invalidated?.Invoke(e.Sender, EventArgs.Empty);
             }
+
+            DashesProperty.Changed.Subscribe(RaiseInvalidated);
+            OffsetProperty.Changed.Subscribe(RaiseInvalidated);
         }
 
+        /// <summary>
+        /// Represents a dashed <see cref="DashStyle"/>.
+        /// </summary>
+        public static IDashStyle Dash =>
+            s_dash ?? (s_dash = new ImmutableDashStyle(new double[] { 2, 2 }, 1));
+
+        /// <summary>
+        /// Represents a dotted <see cref="DashStyle"/>.
+        /// </summary>
+        public static IDashStyle Dot =>
+            s_dot ?? (s_dot = new ImmutableDashStyle(new double[] { 0, 2 }, 0));
+
+        /// <summary>
+        /// Represents a dashed dotted <see cref="DashStyle"/>.
+        /// </summary>
+        public static IDashStyle DashDot =>
+            s_dashDot ?? (s_dashDot = new ImmutableDashStyle(new double[] { 2, 2, 0, 2 }, 1));
+
+        /// <summary>
+        /// Represents a dashed double dotted <see cref="DashStyle"/>.
+        /// </summary>
+        public static IDashStyle DashDotDot =>
+            s_dashDotDot ?? (s_dashDotDot = new ImmutableDashStyle(new double[] { 2, 2, 0, 2, 0, 2 }, 1));
 
-        public DashStyle(IReadOnlyList<double> dashes = null, double offset = 0.0)
+        /// <summary>
+        /// Gets or sets the length of alternating dashes and gaps.
+        /// </summary>
+        public IReadOnlyList<double> Dashes
         {
-            this.Dashes = dashes;
-            this.Offset = offset;
+            get => GetValue(DashesProperty);
+            set => SetValue(DashesProperty, value);
         }
 
         /// <summary>
-        /// Gets and sets the length of alternating dashes and gaps.
+        /// Gets or sets how far in the dash sequence the stroke will start.
         /// </summary>
-        public IReadOnlyList<double> Dashes { get; }
+        public double Offset
+        {
+            get => GetValue(OffsetProperty);
+            set => SetValue(OffsetProperty, value);
+        }
 
-        public double Offset { get; }
+        /// <summary>
+        /// Raised when the dash style changes.
+        /// </summary>
+        public event EventHandler Invalidated;
+
+        /// <summary>
+        /// Returns an immutable clone of the <see cref="DashStyle"/>.
+        /// </summary>
+        /// <returns></returns>
+        public ImmutableDashStyle ToImmutable() => new ImmutableDashStyle(Dashes, Offset);
     }
 }
diff --git a/src/Avalonia.Visuals/Media/IDashStyle.cs b/src/Avalonia.Visuals/Media/IDashStyle.cs
new file mode 100644
index 0000000000..7835c7a1e9
--- /dev/null
+++ b/src/Avalonia.Visuals/Media/IDashStyle.cs
@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+
+namespace Avalonia.Media
+{
+    /// <summary>
+    /// Represents the sequence of dashes and gaps that will be applied by a <see cref="Pen"/>.
+    /// </summary>
+    public interface IDashStyle
+    {
+        /// <summary>
+        /// Gets or sets the length of alternating dashes and gaps.
+        /// </summary>
+        IReadOnlyList<double> Dashes { get; }
+
+        /// <summary>
+        /// Gets or sets how far in the dash sequence the stroke will start.
+        /// </summary>
+        double Offset { get; }
+    }
+}
diff --git a/src/Avalonia.Visuals/Media/IPen.cs b/src/Avalonia.Visuals/Media/IPen.cs
index 589595bb5c..0cdac312cc 100644
--- a/src/Avalonia.Visuals/Media/IPen.cs
+++ b/src/Avalonia.Visuals/Media/IPen.cs
@@ -13,7 +13,7 @@
         /// <summary>
         /// Gets the style of dashed lines drawn with a <see cref="Pen"/> object.
         /// </summary>
-        DashStyle DashStyle { get; }
+        IDashStyle DashStyle { get; }
 
         /// <summary>
         /// Gets the type of shape to use on both ends of a line.
diff --git a/src/Avalonia.Visuals/Media/Immutable/ImmutableDashStyle.cs b/src/Avalonia.Visuals/Media/Immutable/ImmutableDashStyle.cs
new file mode 100644
index 0000000000..a40682babd
--- /dev/null
+++ b/src/Avalonia.Visuals/Media/Immutable/ImmutableDashStyle.cs
@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Avalonia.Media.Immutable
+{
+    /// <summary>
+    /// Represents the sequence of dashes and gaps that will be applied by an
+    /// <see cref="ImmutablePen"/>.
+    /// </summary>
+    public class ImmutableDashStyle : IDashStyle
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ImmutableDashStyle"/> class.
+        /// </summary>
+        /// <param name="dashes">The dashes collection.</param>
+        /// <param name="offset">The dash sequence offset.</param>
+        public ImmutableDashStyle(IEnumerable<double> dashes, double offset)
+        {
+            Dashes = (IReadOnlyList<double>)dashes?.ToList() ?? Array.Empty<double>();
+            Offset = offset;
+        }
+
+        /// <inheritdoc/>
+        public IReadOnlyList<double> Dashes { get; }
+
+        /// <inheritdoc/>
+        public double Offset { get; }
+    }
+}
diff --git a/src/Avalonia.Visuals/Media/Immutable/ImmutablePen.cs b/src/Avalonia.Visuals/Media/Immutable/ImmutablePen.cs
index 326083dec1..ddc050aa5c 100644
--- a/src/Avalonia.Visuals/Media/Immutable/ImmutablePen.cs
+++ b/src/Avalonia.Visuals/Media/Immutable/ImmutablePen.cs
@@ -22,7 +22,7 @@ namespace Avalonia.Media.Immutable
         public ImmutablePen(
             uint color,
             double thickness = 1.0,
-            DashStyle dashStyle = null,
+            ImmutableDashStyle dashStyle = null,
             PenLineCap lineCap = PenLineCap.Flat,
             PenLineJoin lineJoin = PenLineJoin.Miter,
             double miterLimit = 10.0) : this(new SolidColorBrush(color), thickness, dashStyle, lineCap, lineJoin, miterLimit)
@@ -41,7 +41,7 @@ namespace Avalonia.Media.Immutable
         public ImmutablePen(
             IBrush brush,
             double thickness = 1.0,
-            DashStyle dashStyle = null,
+            ImmutableDashStyle dashStyle = null,
             PenLineCap lineCap = PenLineCap.Flat,
             PenLineJoin lineJoin = PenLineJoin.Miter,
             double miterLimit = 10.0)
@@ -67,7 +67,7 @@ namespace Avalonia.Media.Immutable
         /// <summary>
         /// Specifies the style of dashed lines drawn with a <see cref="Pen"/> object.
         /// </summary>
-        public DashStyle DashStyle { get; }
+        public IDashStyle DashStyle { get; }
 
         /// <summary>
         /// Specifies the type of graphic shape to use on both ends of a line.
diff --git a/src/Avalonia.Visuals/Media/Pen.cs b/src/Avalonia.Visuals/Media/Pen.cs
index b89ca15a0e..c0963adc08 100644
--- a/src/Avalonia.Visuals/Media/Pen.cs
+++ b/src/Avalonia.Visuals/Media/Pen.cs
@@ -28,8 +28,8 @@ namespace Avalonia.Media
         /// <summary>
         /// Defines the <see cref="DashStyle"/> property.
         /// </summary>
-        public static readonly StyledProperty<DashStyle> DashStyleProperty =
-            AvaloniaProperty.Register<Pen, DashStyle>(nameof(DashStyle));
+        public static readonly StyledProperty<IDashStyle> DashStyleProperty =
+            AvaloniaProperty.Register<Pen, IDashStyle>(nameof(DashStyle));
 
         /// <summary>
         /// Defines the <see cref="LineCap"/> property.
@@ -68,7 +68,7 @@ namespace Avalonia.Media
         public Pen(
             uint color,
             double thickness = 1.0,
-            DashStyle dashStyle = null,
+            IDashStyle dashStyle = null,
             PenLineCap lineCap = PenLineCap.Flat,
             PenLineJoin lineJoin = PenLineJoin.Miter,
             double miterLimit = 10.0) : this(new SolidColorBrush(color), thickness, dashStyle, lineCap, lineJoin, miterLimit)
@@ -87,7 +87,7 @@ namespace Avalonia.Media
         public Pen(
             IBrush brush,
             double thickness = 1.0,
-            DashStyle dashStyle = null,
+            IDashStyle dashStyle = null,
             PenLineCap lineCap = PenLineCap.Flat,
             PenLineJoin lineJoin = PenLineJoin.Miter,
             double miterLimit = 10.0)
@@ -132,7 +132,7 @@ namespace Avalonia.Media
         /// <summary>
         /// Gets or sets the style of dashed lines drawn with a <see cref="Pen"/> object.
         /// </summary>
-        public DashStyle DashStyle
+        public IDashStyle DashStyle
         {
             get => GetValue(DashStyleProperty);
             set => SetValue(DashStyleProperty, value);
@@ -189,7 +189,7 @@ namespace Avalonia.Media
             return new ImmutablePen(
                 Brush?.ToImmutable(),
                 Thickness,
-                DashStyle,
+                DashStyle?.ToImmutable(),
                 LineCap,
                 LineJoin,
                 MiterLimit);
@@ -247,7 +247,7 @@ namespace Avalonia.Media
             var hashCode = 1181807663;
             hashCode = hashCode * -1521134295 + EqualityComparer<IBrush>.Default.GetHashCode(pen.Brush);
             hashCode = hashCode * -1521134295 + pen.Thickness.GetHashCode();
-            hashCode = hashCode * -1521134295 + EqualityComparer<DashStyle>.Default.GetHashCode(pen.DashStyle);
+            hashCode = hashCode * -1521134295 + EqualityComparer<IDashStyle>.Default.GetHashCode(pen.DashStyle);
             hashCode = hashCode * -1521134295 + pen.LineCap.GetHashCode();
             hashCode = hashCode * -1521134295 + pen.LineJoin.GetHashCode();
             hashCode = hashCode * -1521134295 + pen.MiterLimit.GetHashCode();
@@ -267,7 +267,7 @@ namespace Avalonia.Media
 
             return EqualityComparer<IBrush>.Default.Equals(a.Brush, b.Brush) &&
                a.Thickness == b.Thickness &&
-               EqualityComparer<DashStyle>.Default.Equals(a.DashStyle, b.DashStyle) &&
+               EqualityComparer<IDashStyle>.Default.Equals(a.DashStyle, b.DashStyle) &&
                a.LineCap == b.LineCap &&
                a.LineJoin == b.LineJoin &&
                a.MiterLimit == b.MiterLimit;
diff --git a/tests/Avalonia.Visuals.UnitTests/Media/PenTests.cs b/tests/Avalonia.Visuals.UnitTests/Media/PenTests.cs
index c4fe0155f9..70b4281083 100644
--- a/tests/Avalonia.Visuals.UnitTests/Media/PenTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Media/PenTests.cs
@@ -31,6 +31,19 @@ namespace Avalonia.Visuals.UnitTests.Media
             Assert.True(raised);
         }
 
+        [Fact]
+        public void Changing_DashStyle_Dashes_Raises_Invalidated()
+        {
+            var dashes = new DashStyle();
+            var target = new Pen { DashStyle = dashes };
+            var raised = false;
+
+            target.Invalidated += (s, e) => raised = true;
+            dashes.Dashes = new[] { 0.1, 0.2 };
+
+            Assert.True(raised);
+        }
+
         [Fact]
         public void Equality_Is_Implemented_Between_Mutable_And_Immutable_Pens()
         {
@@ -45,7 +58,7 @@ namespace Avalonia.Visuals.UnitTests.Media
             var target2 = new ImmutablePen(
                 brush: brush,
                 thickness: 2,
-                dashStyle: DashStyle.Dash,
+                dashStyle: (ImmutableDashStyle)DashStyle.Dash,
                 lineCap: PenLineCap.Round,
                 lineJoin: PenLineJoin.Round,
                 miterLimit: 21);