The present invention refers to a wheelchair comprising a frame (20) having spaced apart side frame tubes； a strut (30, 130, 230, 330) connected to the frame； and an adjustable backrest support (10, 10', 10", 400) engaging the strut (30, 130, 230, 330) such that the adjustable backrest support (10, 10', 10", 400) pivots angularly about the strut (30, 130, 230, 330) and being configured to be fixed in one of a plurality of angled positions and moveable along the strut (30, 130, 230, 330) and configured to be fixed in one of a plurality of lateral positions between the side frame tubes. It also refers to an adjustable wheelchair backrest assembly and an adjustable backrest support.
