The Britten-Norman Trislander (more formally designated the BN-2A Mk III Trislander) is an 18-seat triple-engined piston-powered civilian utility aircraft produced by Britten-Norman of Britain.

It is a further development of Britten-Norman's better-known Islander aircraft in order to give it a larger carrying capacity. In comparison with the Islander, the Trislander has a stretched fuselage, modified landing gear and a third (tail-mounted) engine. The prototype of the Trislander, which was constructed from the original second Islander prototype, first flew on September 11, 1970.

The Trislander is capable of taking off from a 450 m long landing strip and can also readily operate from unprepared surfaces.

Among the airlines that have used this airplane are Loganair and Vieques Air Link.