light brown fabric used primarily for military uniforms. It is made with cotton, wool, or combinations of these fibres, as well as with blends of synthetic fibres. It is made in a variety of weaves, such as serge.

Khaki uniforms were introduced by Sir Harry Burnett Lumsden and William Stephen Raikes Hodson in 1848 for British colonial troops in India and were found to be especially effective for field service and battle. Khaki was widely used by the time of the Indian Mutiny (1857–58) and thereafter served as the official colour for uniforms of British armies, native and colonial, in India; later it was adopted in other parts of the British Empire and by other nations.

During the South African War (1899–1902), cotton khaki proved to be unsatisfactory because of climatic conditions, so woolen and worsted serge were introduced. The use of olive tints, which reduce visibility against bare ground and foliage, began during World War I.