Battle of Lang Son

Battle of Lang Son may refer to:
 * The Lạng Sơn Campaign in 1885, a French offensive during the Sino-French War
 * The Battle of Lạng Sơn in September 1940, fought by French forces against the Imperial Japanese Army during the Japanese invasion of French Indochina
 * The Battle of Lang Son (1979) during the Sino-Vietnamese War