The Morane-Saulnier BB was a military observation aircraft produced in France during World War I for use by Britain's Royal Flying Corps.

[1][2] It was a conventional single-bay biplane design with seating for the pilot and observer in tandem, open cockpits.

The original order called for 150 aircraft powered by 110-hp Le Rhône 9J rotary engines, but shortages meant that most of the 94 aircraft eventually built were delivered with 80 hp Le Rhône 9C rotaries instead.

[2] A water-cooled Hispano-Suiza 8A engine was trialled as an alternative in the Type BH, but this remained experimental only.

[1] A production licence was sold to the Spanish company Compañía Española de Construcciones Aeronáuticas (CECA), which built twelve fitted with Hispano-Suiza engines in 1916.