A surface-to-air missile (also known as SAM), ground-to-air missile (GTAM) or surface-to-air guided weapons (SAGW), is a missile designed to be launched to destroy ground aircraft or other missiles. It is a kind of anti-aircraft system; In the modern armed forces, missiles and most other forms of special anti-aircraft guns are replaced by anti-aircraft specialized roles.

The first serious attempts at SAM development took place during World War II, even though no operating system was used. Further development in the 1940s and 1950s led to the introduction of operational systems by most major powers in the second half of the 1950s. Smaller systems suitable for close range operation evolved into modern human-portable systems in the 1960s and 1970s. Ship-borne systems followed the evolution of land-based models, starting with long-range weapons and gradually evolving into smaller designs to provide layered defense. This evolution of design has increasingly pushed weapon-based systems into shortest-range roles.

The American Nike Ajax was the first operational guided missile SAM system, and the Soviet Union's S-75 Dvina was the most produced SAM. Commonly used modern examples include the Patriot and S-300 wide area systems, the SM-6 and MBDA Aster Missile naval missiles, and short-range man-portable systems such as Stinger and Strela-3.