A raising wheelchair comprises a wheeled frame and a raising system mounted to the frame and supporting a seat and a backrest. The raising system is configured to be movable between a lowered position and a raised position. The raising system includes at least one double-armed lever including a first lever member and a second lever member, a coupling member fixedly mounted to the frame, wherein the first lever member and the second lever member are pivotally coupled to the coupling member, and a coupling mechanism translationally coupled or pivotally coupled to a second end of the first lever member, pivotally coupled to a second end of the second lever member, and coupled to the backrest. The raising system maintains an orientation of the backrest relative to the ground that is substantially constant throughout substantially an entire range of movement between the lowered position and the raised position.