The Bac Le ambush (, Vietnamese: trận Bắc Lệ or trận cầu Quan Âm) was a clash during the Tonkin Campaign in June 1884 between Chinese troops of the Guangxi Army and a French column sent to occupy Lang Son and other towns near the Chinese border. The French claimed that their troops had been ambushed by the Chinese. The incident led to the Sino-French War (August 1884–April 1885).