diff --git a/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Editor/SubclassSelectorDrawer.cs b/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Editor/SubclassSelectorDrawer.cs
index 3525a37..0e5f746 100644
--- a/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Editor/SubclassSelectorDrawer.cs
+++ b/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Editor/SubclassSelectorDrawer.cs
@@ -63,7 +63,6 @@ namespace MackySoft.SerializeReferenceExtensions.Editor {
 				Type baseType = property.GetManagedReferenceFieldType();
 				var popup = new AdvancedTypePopup(
 					TypeCache.GetTypesDerivedFrom(baseType).Where(p =>
-						p.IsClass &&
 						(p.IsPublic || p.IsNestedPublic) &&
 						!p.IsAbstract &&
 						!p.IsGenericType &&
diff --git a/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/Example.unity b/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/Example.unity
index 7de6c63..86338ed 100644
--- a/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/Example.unity
+++ b/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/Example.unity
@@ -334,6 +334,7 @@ MonoBehaviour:
   - id: 1
   - id: 2
   - id: 3
+  - id: 4
   references:
     version: 1
     00000000:
@@ -348,6 +349,8 @@ MonoBehaviour:
       type: {class: Example/NestedCommand, ns: MackySoft.SerializeReferenceExtensions.Example, asm: Assembly-CSharp}
     00000003:
       type: {class: AddTypeMenuCommand, ns: MackySoft.SerializeReferenceExtensions.Example, asm: Assembly-CSharp}
+    00000004:
+      type: {class: StructCommand, ns: MackySoft.SerializeReferenceExtensions.Example, asm: Assembly-CSharp}
 --- !u!4 &1098750747
 Transform:
   m_ObjectHideFlags: 0
diff --git a/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/ExampleAssets/Scripts/Runtime/Example.cs b/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/ExampleAssets/Scripts/Runtime/Example.cs
index 570c109..301e54d 100644
--- a/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/ExampleAssets/Scripts/Runtime/Example.cs
+++ b/Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Example/ExampleAssets/Scripts/Runtime/Example.cs
@@ -69,5 +69,12 @@ namespace MackySoft.SerializeReferenceExtensions.Example {
 		}
 	}
 
+	[Serializable]
+	public struct StructCommand : ICommand {
+		public void Execute () {
+			Debug.Log("Execute StructCommand");
+		}
+	}
+
 }
 #endif
\ No newline at end of file
diff --git a/README.md b/README.md
index 7c497e4..14a973d 100644
--- a/README.md
+++ b/README.md
@@ -111,13 +111,19 @@ public class AddTypeMenuCommand : ICommand {
 		Debug.Log("Execute AddTypeMenuCommand");
 	}
 }
+
+[Serializable]
+public struct StructCommand : ICommand {
+	public void Execute () {
+		Debug.Log("Execute StructCommand");
+	}
+}
 ```
 
 #### Supported Types
 
 The `SubclassSelector` attribute supports types that meet the following conditions.
 
-- Class
 - Public
 - Not abstract
 - Not generic