A wheelchair comprising a frame, a seat assembly attached to the frame, two rear wheels attached to the frame, and at least one front wheel assembly attached to the frame. The frame defines a front face and two side faces. The front face is defined by one or more structural elements situated along a front of the frame, while the side faces are defined by two top side members and two corresponding bottom side members. The front face and the two side faces result in three non-orthogonal planes, which contribute to the strength and stiffness of the frame.