A system for attaching a wheelchair back to wheelchair posts comprising a bracket and interchangeable attachment hardware secured to the bracket. In one aspect the bracket can be adjusted vertically relative to the wheelchair back and can be adjusted on a horizontal path. In one aspect, the angular orientation of the attachment hardware can be adjusted to adjust the angular position of the wheelchair back relative to the wheelchair seat and posts. In one aspect the attachment hardware is represented by a hanger assembly. In one aspect the attachment hardware is represented by an expansion plug assembly for insertion into the open tubular end of a wheelchair post.