diff --git a/dydx3/modules/private.py b/dydx3/modules/private.py
index 9b6fda6..5d613d2 100644
--- a/dydx3/modules/private.py
+++ b/dydx3/modules/private.py
@@ -451,6 +451,7 @@ def create_order(
         expiration=None,
         expiration_epoch_seconds=None,
         signature=None,
+        reduce_only=None,
     ):
         '''
         Post an order
@@ -520,6 +521,9 @@ def create_order(
         :param signature: optional
         type signature: str
 
+        :param reduce_only: optional
+        type reduce_only: bool
+
         :returns: Order
 
         :raises: DydxAPIError
@@ -572,6 +576,7 @@ def create_order(
             'postOnly': post_only,
             'clientId': client_id,
             'signature': order_signature,
+            'reduceOnly': reduce_only,
         }
 
         return self._post(