Ossa was a Spanish motorcycle manufacturer which was active from 1924 to 1982 and from 2010 to 2015. Founded by Manuel Giró, an industrialist from Barcelona, Ossa was best known for lightweight, two-stroke-engined bikes used in observed trials, motocross and enduro. The company was known originally as Orpheo Sincronic Sociedad Anónima (O.S.S.A.) and was later renamed Maquinaria Cinematográfica, S.A..

Motocross is a form of off-road motorcycle racing held on enclosed off-road circuits. The sport evolved from motorcycle trials competitions held in the United Kingdom.