diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
index 000079412505..5b91b6bb5cd2 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
@@ -150,6 +150,11 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             attrNoneIfUnset = Boolean.valueOf(additionalProperties.get(CodegenConstants.PYTHON_ATTR_NONE_IF_UNSET).toString());
         }
         additionalProperties.put("attrNoneIfUnset", attrNoneIfUnset);
+
+        // check library option to ensure only urllib3 is supported
+        if (!DEFAULT_LIBRARY.equals(getLibrary())) {
+            throw new RuntimeException("Only the `urllib3` library is supported in the refactored `python` client generator at the moment. Please fall back to `python-legacy` client generator for the time being. We welcome contributions to add back `asyncio`, `tornado` support to the `pyhton` client generator.");
+        }
     }
 
     /**