diff --git a/Structurizr.Core.Tests/View/ConfigurationTests.cs b/Structurizr.Core.Tests/View/ConfigurationTests.cs
index 47af3a2..7406fd3 100644
--- a/Structurizr.Core.Tests/View/ConfigurationTests.cs
+++ b/Structurizr.Core.Tests/View/ConfigurationTests.cs
@@ -1,4 +1,5 @@
-using Xunit;
+using System;
+using Xunit;
 
 namespace Structurizr.Core.Tests
 {
@@ -33,6 +34,47 @@ public void test_copyConfigurationFrom()
             ViewConfiguration destination = new ViewConfiguration();
             destination.CopyConfigurationFrom(source);
             Assert.Equal("someKey", destination.LastSavedView);
+        } 
+        
+        [Fact]
+        public void Test_SetTheme_WithAUrl()
+        {
+            ViewConfiguration configuration = new ViewConfiguration();
+            configuration.Theme = "https://example.com/theme.json";
+            Assert.Equal("https://example.com/theme.json", configuration.Theme);
+        }
+
+        [Fact]
+        public void Test_SetTheme_WithAUrlThatHasATrailingSpaceCharacter()
+        {
+            ViewConfiguration configuration = new ViewConfiguration();
+            configuration.Theme = "https://example.com/theme.json ";
+            Assert.Equal("https://example.com/theme.json", configuration.Theme);
+        }
+
+        [Fact]
+        public void Test_SetTheme_ThrowsAnIllegalArgumentException_WhenAnInvalidUrlIsSpecified()
+        {
+            ViewConfiguration configuration = new ViewConfiguration();
+            Assert.Throws<ArgumentException>(() =>
+                configuration.Theme = "blah"
+            );
+        }
+
+        [Fact]
+        public void Test_SetTheme_DoesNothing_WhenANullUrlIsSpecified()
+        {
+            ViewConfiguration configuration = new ViewConfiguration();
+            configuration.Theme = null;
+            Assert.Null(configuration.Theme);
+        }
+
+        [Fact]
+        public void Test_SetTheme_DoesNothing_WhenAnEmptyUrlIsSpecified()
+        {
+            ViewConfiguration configuration = new ViewConfiguration();
+            configuration.Theme = " ";
+            Assert.Null(configuration.Theme);
         }
 
     }
diff --git a/Structurizr.Core/View/ViewConfiguration.cs b/Structurizr.Core/View/ViewConfiguration.cs
index 44a58b8..0a0c8da 100644
--- a/Structurizr.Core/View/ViewConfiguration.cs
+++ b/Structurizr.Core/View/ViewConfiguration.cs
@@ -1,5 +1,7 @@
+using System;
 using System.Runtime.Serialization;
 using Structurizr.Core.View;
+using Structurizr.Util;
 
 namespace Structurizr
 {
@@ -21,6 +23,27 @@ internal ViewConfiguration()
         [DataMember(Name = "styles", EmitDefaultValue = false)]
         public Styles Styles { get; internal set; }
 
+        private String _theme;
+        
+        [DataMember(Name = "theme", EmitDefaultValue = false)]
+        public string Theme
+        {
+            get { return _theme; }
+            set
+            {
+                if (value != null && value.Trim().Length > 0)
+                {
+                    if (Url.IsUrl(value))
+                    {
+                        _theme = value.Trim();
+                    }
+                    else {
+                        throw new ArgumentException(value + " is not a valid URL.");
+                    }
+                }
+            }
+        }
+        
         [DataMember(Name = "branding", EmitDefaultValue = false)]
         public Branding Branding { get; internal set; }
 
diff --git a/docs/changelog.md b/docs/changelog.md
index cfd51db..bae51be 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -3,6 +3,7 @@
 ## 0.9.6 (unreleased)
 
 - Added A1 and A0 paper sizes.
+- Adds support for themes.
 
 ## 0.9.5 (24th December 2019)