Wanderers' cleanout continues
Appiah, 22, was one of the club's first three signings – but he struggled to cement a regular place.
His departure comes a day after Daniel Mullen left, while Vitor Saba has also made way in January.
Wanderers chief executive John Tsatsimas paid tribute to Appiah.
“Kwabena is one of the club’s success stories; signed as a local Western Sydney boy, he is now an accomplished Hyundai A-League player and Asian champion,” he said in a statement.
“It has been a pleasure to watch Kwabena grow as a player and as a person and we wish him nothing but the best for the rest of his career.
“Kwabena will never be forgotten by the fans, staff or team-mates and he leaves us with great memories and a lot of smiles.”
Tony Popovic's men are winless in 12 A-League games this season, sitting bottom of the table.
They have made several inclusions during January, including signing Yojiro Takahagi, as they look to turn their campaign around.