A stroller frame having forwardly extending right and left side front supports, rearwardly extending right and left side rear supports, and upwardly extending right and left side handle supports moveable connected to permit movement of the frame between deployed and collapsed orientations, and a folding seat frame connected to the front and rear supports having right and left side fold mechanisms which are configured to lock the frame in the deployed or collapsed configurations and to selectively bias frame members toward movement towards the deployed or collapsed configurations based on frame orientation and operation of a release handle.