The Aérospatiale Gazelle originated in a French Army requirement for a lightweight utility helicopter. The design quickly attracted British interest, leading to a development and production shareout agreement with British company Westland Helicopters (later AgustaWestland). The deal, signed in February 1967, allowed the production in Britain of 292 Gazelles and 48 Aérospatiale Pumas ordered by the British armed forces, in return Aérospatiale were given a workshare in the manufacturing programme for the 40 Westland Lynx naval helicopters for the French Navy.

Though the general layout resembles that of the Alouette series, the Gazelle featured several important innovations. This was the first helicopter to carry a fenestron or fantail, which allows considerable noise reduction. Also, the rotor blades were made of composite materials, a feature now widely used in modern helicopters.

In service with the French Army Light Aviation, the ALAT, the Gazelle is used primarily as an anti-tank gunship (SA 342M) armed with HOT missiles. A light support version equipped with a 20 mm cannon is used (SA 341F) as well as anti-air variants carrying the Mistral air-to-air missile (Gazelle Celtic based on the SA 341F, Gazelle Mistral based on the SA 342M). The latest anti-tank and reconnaissance versions carry the Viviane thermal imagery system and so are called Gazelle Viviane. The Gazelle is being replaced in frontline duties by the Eurocopter Tiger but will continue to be used for light transport and liaison roles.

It also served with all branches of the British armed forces—the Royal Air Force, Royal Navy (including Royal Marines) and the British Army in a variety of roles. Four versions of the Gazelle were used by the British Forces. The SA341D became the Gazelle HT.3 in RAF service, equipped as a helicopter pilot trainer (hence HT). The SA 341E was used for communications duties and VIP transport and as the Gazelle HCC.4. The SA 341C was purchased as the Gazelle HT.2 pilot trainer for the Royal Navy. The training variants have now been replaced by the Squirrel HT1. The SA 341B was equipped to a specification for the Army Air Corps as the Gazelle AH.1 (from Army Helicopter Mark 1). It was used as an Air Observation Post (AOP) for directing artillery fire, Airborne Forward Air Controller (ABFAC) directing ground-attack aircraft, casualty evacuation, liaison, and command and control, and communications relay.