diff --git a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt
index 82d18736c5..c1e244b05b 100644
--- a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt
+++ b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt
@@ -655,6 +655,7 @@ namespace ReactiveUI
         Uno = 3,
         Blazor = 4,
         Drawing = 5,
+        Avalonia = 6,
     }
     public class Registrations
     {
diff --git a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt
index 333a0d3eca..3154b3f96c 100644
--- a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt
+++ b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt
@@ -650,6 +650,7 @@ namespace ReactiveUI
         Uno = 3,
         Blazor = 4,
         Drawing = 5,
+        Avalonia = 6,
     }
     public class Registrations
     {
diff --git a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt
index 35e6b5c4f1..0ca16ef123 100644
--- a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt
+++ b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt
@@ -648,6 +648,7 @@ namespace ReactiveUI
         Uno = 3,
         Blazor = 4,
         Drawing = 5,
+        Avalonia = 6,
     }
     public class Registrations
     {
diff --git a/src/ReactiveUI/RegistrationNamespace.cs b/src/ReactiveUI/RegistrationNamespace.cs
index e5c38e8d94..3cecdd51f2 100644
--- a/src/ReactiveUI/RegistrationNamespace.cs
+++ b/src/ReactiveUI/RegistrationNamespace.cs
@@ -38,6 +38,11 @@ public enum RegistrationNamespace
         /// <summary>
         /// Drawing.
         /// </summary>
-        Drawing
+        Drawing,
+
+        /// <summary>
+        /// Avalonia.
+        /// </summary>
+        Avalonia
     }
 }