The Salmson 2, (given the military designation Salmson 2 A2) was a French biplane reconnaissance aircraft made by Salmson. It was developed to a 1916 requirement. Along with the Breguet 14, it was the main reconnaissance aircraft in use with the French army in 1918. At the end of the First World War, one-third of French reconnaissance aircraft were Salmson 2s.
After WWI the Japanese built copies of the Salmson 2A2 and named their version the Otsu-1.