A knee walker includes a frame; a cushion; a front crossmember; two rear wheels; two front spindles and two front wheels each pivotally connected to one of the two front spindles. Positive steering is provided by a handlebar rotatably connected to the front end of the frame; a steering gear responsively engaged with the rotatably connected handlebar shaft; a steering arm actuated by the steering gear responsive to the handlebar; a steering rod connecting the steering arm and one of the two front spindles, so as to pivot one associated front wheel responsive to the steering arm; and a tie rod linking the two front spindles responsively to the steering rod.