diff --git a/unity/Runtime/Components/Tendons/MjSpatialTendon.cs b/unity/Runtime/Components/Tendons/MjSpatialTendon.cs
index cfff6c0b..e43f587b 100644
--- a/unity/Runtime/Components/Tendons/MjSpatialTendon.cs
+++ b/unity/Runtime/Components/Tendons/MjSpatialTendon.cs
@@ -16,9 +16,10 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using System.Runtime.InteropServices.ComTypes;
 using System.Xml;
+#if UNITY_EDITOR
 using UnityEditor;
+#endif
 using UnityEngine;
 
 namespace Mujoco {