An M.2 fastening system has an M.2 riser card with two module-receiving sides and a plurality of adjustment positions. The M.2 fastening system further has a pair of M.2 fasteners mounted respectively on the module-receiving sides. Each M.2 fastener has a main body defined by a top surface and a bottom surface; a module attachment extending from the top surface; and a hook extending from the bottom surface along a lateral side of the main body. The hook of one of the M.2 fasteners is received through an attachment aperture of an adjustment position. The hook is pressed-fit over the top surface of the main body of another M.2 fastener. The hook secures the M.2 riser card between the pair of M.2 fasteners in a tool-less manner.