diff --git a/tweepy/client.py b/tweepy/client.py
index e3b445b64..1077e174f 100644
--- a/tweepy/client.py
+++ b/tweepy/client.py
@@ -143,7 +143,7 @@ def _make_request(self, method, route, params={}, endpoint_parameters=None,
 
             if isinstance(param_value, list):
                 request_params[param_name] = ','.join(map(str, param_value))
-            elif param_name in ("start_time", "end_time") and isinstance(param_value, datetime.datetime):
+            elif isinstance(param_value, datetime.datetime):
                 if param_value.tzinfo is not None:
                     param_value = param_value.astimezone(datetime.timezone.utc)
                 request_params[param_name] = param_value.strftime("%Y-%m-%dT%H:%M:%S.%fZ")