Omega Speedmaster is a line of chronograph wristwatches produced by Omega SA. While chronographs have existed since the late 1800s, Omega first introduced this line of chronographs in 1957. Since then, many different chronograph movements have been marketed under the Speedmaster name. Astronaut Walter Schirra was the first person to wear one in space in 1962 during his Mercury-Atlas 8 mission. The manual winding Speedmaster Professional or "Moonwatch" is the best-known and longest-produced; it was worn during the first American spacewalk as part of NASA's Gemini 4 mission, and was the first watch worn by an astronaut walking on the Moon during the Apollo 11 mission. 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 other models, including analog-digital and automatic mechanical watches.

A chronograph is a specific type of watch that is used as a stopwatch combined with a display watch. A basic chronograph has an independent sweep second hand and a minute sub-dial; it can be started, stopped, and returned to zero by successive pressure on the stem. More complex chronographs use additional complications and can have multiple sub-dials to measure seconds, minutes, hours and even fractions of a second. In addition, many modern chronographs use moveable bezels as tachymeters for rapid calculations of speed or distance. Louis Moinet invented the chronograph in 1816 for use in tracking astronomical objects. Chronographs were also used heavily in artillery fire in the mid to late 1800s. More modern uses of chronographs involve aircraft piloting, auto racing, diving and submarine maneuvering.