diff --git a/tplus/model/order.py b/tplus/model/order.py
index 204fe36..2dfd03f 100644
--- a/tplus/model/order.py
+++ b/tplus/model/order.py
@@ -72,6 +72,7 @@ class Order(BaseModel):
     creation_timestamp_ns: int
     canceled: bool = False
     target: TradeTarget = TradeTarget.margin_account_spot_trade()
+    reduce_only: bool = False
     protocol_version: int = 1
 
     def signable_part(self) -> str:
@@ -114,6 +115,7 @@ class OrderResponse(BaseModel):
     is_immediate_or_cancel: bool | None = None
     is_fill_or_kill: bool | None = None
     is_liquidation: bool | None = None
+    is_reduce_only: bool | None = None
 
 
 def parse_orders(orders_data: list[dict[str, Any]]) -> list[OrderResponse]:
diff --git a/tplus/utils/limit_order.py b/tplus/utils/limit_order.py
index 63e078b..96da5d8 100644
--- a/tplus/utils/limit_order.py
+++ b/tplus/utils/limit_order.py
@@ -19,6 +19,7 @@ def create_limit_order_ob_request_payload(
     time_in_force: GTC | GTD | IOC | None = None,
     trigger: OrderTrigger | None = None,
     target: TradeTarget | None = None,
+    reduce_only: bool = False,
 ) -> CreateOrderRequest:
     side_normalized = Side.SELL if side.lower() == "sell" else Side.BUY
 
@@ -41,6 +42,7 @@ def create_limit_order_ob_request_payload(
         trigger=trigger,
         creation_timestamp_ns=time.time_ns(),
         target=actual_target,
+        reduce_only=reduce_only,
     )
     sign_payload_json = order.signable_part()
     signature_bytes = signer.sign(sign_payload_json)
diff --git a/tplus/utils/market_order.py b/tplus/utils/market_order.py
index 77f6b79..7288150 100644
--- a/tplus/utils/market_order.py
+++ b/tplus/utils/market_order.py
@@ -24,6 +24,7 @@ def create_market_order_ob_request_payload(
     fill_or_kill: bool = False,
     trigger: OrderTrigger | None = None,
     target: TradeTarget | None = None,
+    reduce_only: bool = False,
 ) -> CreateOrderRequest:
     side_normalized = Side.SELL if side.lower() == "sell" else Side.BUY
 
@@ -43,6 +44,7 @@ def create_market_order_ob_request_payload(
         trigger=trigger,
         creation_timestamp_ns=time.time_ns(),
         target=actual_target,
+        reduce_only=reduce_only,
     )
 
     sign_payload_json = order.signable_part()