Garelli Motorcycles was an Italian moped and motorcycle manufacturer. It was founded in 1919 by Alberto Garelli.
At age 22, Adalberto Garelli received a degree in engineering and dedicated his work to developing and perfecting the two-strokeengine for Fiat. Garelli quit in 1911 due to Fiat's lack of enthusiasm for the two-stroke engine. He continued his own engine design between 1911 and 1914 which resulted in the 350 cc split-single cylinder engine. Garelli worked for other motorcycle manufacturers from 1914 to 1918 during which time he won a competition organized by the Italian Army to design a motorcycle with which he used his 350 cc split-single engine.
In 1919, Garelli constructed a 350 cc motorcycle which set a long distance record from Milan to Naples. Rider Ettore Girardi covered the 840 km (520 mi) with an average of 38.29 km/h (24 mph). Many famous Italian racers such as Ernesto Gnesa, Tazio Nuvolari and Achille Varzi began their racing careers on Garelli bikes. The Garelli 350 cc split-single stayed in production until 1926 and made a major impact in racing. The company also produced motorcycles for the Italian military. After World War II, Garelli concentrated on producing smaller bikes and mopeds for the European market.