The Le Rhône 9C is a nine-cylinder rotary aircraft engine produced in France by Société des Moteurs Le Rhône / Gnome et Rhône. Also known as the Le Rhône 80 hp in a reference to its nominal power rating, the engine was fitted to many military aircraft types during the First World War. Le Rhône 9C engines were also produced under license in Great Britain, the United States and Sweden.

Gnome et Rhône was a major French aircraft engine manufacturer. Between 1914 and 1918 they produced 25,000 of their 9-cylinder Delta and Le Rhône 110 hp (81 kW) rotary designs, while another 75,000 were produced by various licensees. These engines powered the majority of aircraft in the first half of the war, both Allied designs as well as German examples produced by Motorenfabrik Oberursel.