A bicycle frame includes a frame body including a top tube, a seat tube, a seat stay, and a mounting unit that is disposed at a junction among the top tube, the seat tube and the seat stay, and that has a base portion, and a position-limiting portion extending from the base portion, a seat post unit including a seat post that extends through the base portion, and a post clamp that is fixedly sleeved onto the seat post, and that is retained in the frame body by the position-limiting portion, a cushion sleeved onto the seat post, and having a tube body that is fittingly disposed between the seat post and the base portion, and a sleeve portion that extends from the tube body, and that is disposed between the post clamp and the base portion.