An apparatus is disclosed for use on standard or customized wheelchairs for moving the wheelchair and wheelchair occupant up or down a stairway or stairway-like structure (e.g., a curb) with greater confidence and stability to the occupant of the wheelchair and its handler(s). The apparatus includes a motorized assembly that interacts with stair steps when the apparatus and wheelchair are tilted backwardly. The motorized assembly allows the wheelchair to glide or move up or down the steps without experiencing the bumps commonly associated with rolling a wheelchair up or down a set of stairs. The apparatus includes a headrest to provide comfort to the occupant during operation and includes pivoting handlebars to allow the operator of the wheelchair to control the movement of the wheelchair. The apparatus is mountable to, and removable from (when not in use), the wheelchair. The apparatus can be considered as a retrofit.