Omega Speedmaster is a brand of chronograph wristwatches produced by the Omega Watch Company. Many different watches have been marketed under the Speedmaster name over the years. The manual winding Speedmaster Professional or "Moonwatch" is the most well-known and longest-produced; it was worn during the first American spacewalk during Gemini 4 and was the first watch worn on the moon during Apollo 11. The Speedmaster Professional remains one of several watches qualified by NASA for spaceflight and is still the only one so qualified for EVA.

The Speedmaster line also includes a multitude of other models, including analog-digital and automatic mechanical watches.

The Speedmaster was not originally designed for space exploration. Instead, it was introduced in 1957 as a sports and racing chronograph, complementing Omega's position as the official timekeeper for the Olympic Games.

The first Speedmaster model, the reference CK 2915 was released in 1957. It was powered by the Omega Calibre 321, developed in 1946 by Albert Piguet of Lemania, which had been acquired in 1932 by Omega's parent company, SSIH. The "Speedmaster" name was coined from the model's novel tachymeter scale bezel (in brushed stainless steel) and by the convention set by prior Omega brands Seamaster and Railmaster.

The model established the series's hallmark 12-hour, triple-register chronograph layout, domed Plexiglas crystal, and simple, high-contrast index markers; but, unlike most subsequent Speedmaster models, it used Omega's Broadarrow hand set. In 1959, a second version, CK 2998, was released with a black aluminum tachymeter bezel and alpha hands. This was again updated in 1963 by references ST 105.003 with straight baton hands and ST 105.012 with an asymmetrical case to protect the chronograph pushers and crown.