The Messerschmitt-Bölkow-Blohm Bo105 is a light, twin-engine, multi-purpose helicopter developed by Bölkow of Ottobrunn, West Germany (now Germany). It was the first light twin-engine helicopter in the world, and the first rotorcraft that could perform aerobatic maneuvers such as inverted loops. The Bo105 features a revolutionary hingeless rotor system, at that time a pioneering innovation in helicopters when it was introduced into service in 1970. Production of the Bo105 began at the then-recently merged Messerschmitt-Bölkow-Blohm (MBB).
The main production facilities for producing the Bo105 were located in Germany and Canada; due to the level of export sales encountered, additional manufacturing lines were set up in Spain, Indonesia, and the Philippines. MBB became a part of Eurocopter GmbH in 1991, who continued production of the type until 2001. The Bo105 was formally replaced in Eurocopter's product range by the newer Eurocopter EC135, which was itself a development of the Bo105.