diff --git a/LightweightIocContainer.Validation/IocValidator.cs b/LightweightIocContainer.Validation/IocValidator.cs
index df33fc2..5d9e259 100644
--- a/LightweightIocContainer.Validation/IocValidator.cs
+++ b/LightweightIocContainer.Validation/IocValidator.cs
@@ -89,6 +89,9 @@ public class IocValidator
 
         if (type == typeof(string))
             return string.Empty;
+
+        if (type.IsInterface)
+            return new NullParameter(type);
             
         try
         {