Rapier is a surface-to-air missile developed for the British Army to replace their towed Bofors 40/L70 anti-aircraft guns. The system is unusual as it uses a manual optical guidance system, sending guidance commands to the missile in flight over a radio link. This results in a high level of accuracy, therefore a large warhead is not required.

Entering service in 1971, it eventually replaced all other anti-aircraft weapons in British Army service; both the Bofors guns used against low-altitude targets and the Thunderbird missile used against longer-range and higher-altitude targets. As the expected air threat moved from medium-altitude strategic missions to low-altitude strikes, the fast reaction time and high manoeuvrability of the Rapier made it more effective than either of these weapons, replacing most of them by 1977.

Rapier was later selected by the RAF Regiment to replace their Bofors guns and Tigercat missiles. It also saw international sales. As of 2021, it was in the process of being replaced as one of the UK's primary air-defence weapons by Sky Sabre.