diff --git a/src/Refitter.Core/CSharpClientGeneratorFactory.cs b/src/Refitter.Core/CSharpClientGeneratorFactory.cs
index 279b6958..6b1030e3 100644
--- a/src/Refitter.Core/CSharpClientGeneratorFactory.cs
+++ b/src/Refitter.Core/CSharpClientGeneratorFactory.cs
@@ -62,6 +62,12 @@ public CustomCSharpClientGenerator Create()
             settings.CodeGeneratorSettings,
             generator.Settings.CSharpGeneratorSettings);
 
+        // Auto-enable optional properties as nullable when nullable reference types enabled
+        if (generator.Settings.CSharpGeneratorSettings.GenerateNullableReferenceTypes)
+        {
+            generator.Settings.CSharpGeneratorSettings.GenerateOptionalPropertiesAsNullable = true;
+        }
+
         return generator;
     }