A curb-climbing rear wheel drive power wheelchair is disclosed having a pair of drive wheels, at least one ground-engaging idler wheel connected to the frame forward of the drive wheels and at least one ground-contacting anti-tip caster wheel mounted to the wheelchair aft of the drive wheels. The drive wheels and anti-tip caster wheels are mounted on common suspension arms, pivoted to the frame of the wheelchair behind the drive wheels and resiliently suspended, so that the anti-tip caster wheels move up and down in response to movements of the drive wheel suspension.