The Agusta A109 is a helicopter manufactured by Agusta (now AgustaWestland) of Italy. It is a light-weight, twin engine, eight seat multi-purpose helicopter.

In the late 1960s Agusta designed the A109A as a single-engined commercial helicopter. It was soon realised that a twin-engined design was needed and it was re-designed in 1967 with two Allison 250-C14 turboshaft engines.

A projected military version (the A109B) was not developed and the company concentrated on the eight-seat version the A109C. The first of three prototypes first flew on the 4 August 1971.

A long protracted development then followed and the first production aircraft was not completed until April 1975. Delivery of production machines started in early 1976. The aircraft soon became a success and was soon used for roles other than as a light transport including as an air ambulance and search-and-rescue. In 1975 Agusta returned again to the possibility of a military version and trials were carried out between 1976 and 1977 with five A109As fitted with Hughes Aircraft TOW missiles. Two military versions were then developed, one for light attack or close support and another for naval operations.