Abstract: A snap fastener tool for use in applying boat covers, vehicle tops, etc., where mating snap fastener halves on a canvas or fabric cover and on a fixed frame must be brought into coupling alignment with each other. An elongate rigid handle is formed with a rearwardly facing shoulder projecting from one side of the handle near its front end for engagement with the fastener half on the cover and a jack arm is pivotally mounted on the handle intermediate its ends for engagement with the fastener half on the fixed frame and for pivotal movement into and out of rearwardly spaced opposed relationship with the shoulder. As the handle and jack lever are pivoted opposed, concave fastener seats on the shoulder and front end of the jack arm and engaging the fastener halves force the latter into alignment with each other and join them together.