The AgustaWestland AW109, originally the Agusta A109, is a lightweight, twin-engine, eight-seat multi-purpose helicopter designed and initially produced by the Italian rotorcraft manufacturer Agusta. It was the first all-Italian helicopter to be mass-produced. Its production has been continued by Agusta's successor companies, presently Leonardo, formerly AgustaWestland, merged into the new Finmeccanica since 2016.
Development of the A109 commenced during the late 1960s as an indigenous rotorcraft suited to commercial operations. A twin-engine arrangement was pursued in response to market interest, while work on the civil model was prioritised over the military-orientated A109B project. On 4 August 1971, the first of three prototypes made its maiden flight. On 1 June 1975, the type received certification from the Federal Aviation Administration (FAA), permitting its service entry in 1976. The A109 has been used in a wide variety of roles, including light utility, VIP transport, aeromedical, law enforcement, search and rescue (SAR), and several military roles. Dedicated military models have been produced for both land and sea operations. Several models with alternative engines, expanded fuselages, and alternative equipment fitouts have been produced. Some AW109s feature a convertible interior to quickly adapt the rotorcraft between roles. Various third-party companies also offer adaptions and services for the type.