A system and method for transmission control protocol (TCP) acceleration. Incoming acknowledgement (ACK) packets belonging to a TCP session are received, and an upstream queue is searched for queued acknowledgment packets belonging to the same TCP session. If the incoming acknowledgment packet is not a duplicate of the queued acknowledgment packet, one of the queued acknowledgment packets is replaced with the incoming acknowledgment packet in the position in the upstream queue occupied by the oldest of the queued acknowledgment packets. After the oldest queued acknowledgement packet is replaced, remaining acknowledgement packets in the queue are dropped.