diff --git a/src/extensions/ext_hooks.cpp b/src/extensions/ext_hooks.cpp
index 5d54e681b..619520781 100644
--- a/src/extensions/ext_hooks.cpp
+++ b/src/extensions/ext_hooks.cpp
@@ -132,6 +132,15 @@ void Extension_Hooks()
      */
     SaveLoad_Hooks();
 
+    /**
+     *  Command line option to disable class extensions.
+     */
+    const char *cmdline = GetCommandLineA();
+    bool no_class_extensions = (std::strstr(cmdline, "-NO_EXT") != nullptr);
+    if (no_class_extensions) {
+        return;
+    }
+
     /**
      *  Various functions.
      */