The Pentax MX was a 35 mm single-lens reflex camera produced by Asahi Optical Co, later Pentax of Japan between 1976 and 1985. It was Pentax's flagship professional SLR until the introduction of the Pentax LX. Internally, the MX is essentially a smaller, lighter version of the Pentax KX, and otherwise has little in common with the rest of the Pentax M-series. However, the MX was designed as the mechanical twin sister of the remarkably successful entry-level Pentax ME.