The Diamant rocket (French for "diamond") was the first exclusively French expendable launch system and at the same time the first satellite launcher not built by either the United States or USSR. As such, it has been referred to as being a key predecessor for all subsequent European launcher projects.

During 1962, development of the Diamant commenced as the inaugural spacecraft project of France's space agency, the Centre National d'Études Spatiales (CNES). As a project, it was derived from the military program Pierres précieuses (fr.: gemstones) that included the five prototypes Agate, Topaze, Emeraude, Rubis and Saphir (Agate, Topaz, Emerald, Ruby and Sapphire), and drew heavily upon the knowledge and technologies that had been previously developed. On 26 November 1965, the Diamant A performed its maiden flight. Out of a total of 12 launch attempts to be performed between 1965 and 1975, 9 of these were successful. Most notably, on 26 November 1965, the Diamant was used to successfully launch the first French satellite, named Astérix.

Three successive versions of the Diamant rocket were developed, designated A, B and BP4. All versions had three stages and a payload of approximately 150 kg for a 200 km orbit. Despite the success of the Diamant as a launcher, France ultimately chose to terminate further work on its national launcher program in favor of participation in the multi-European programme to produce what would become the Ariane launcher in 1975.