Decaux, or De Caux, is a French surname. Notable people with the surname include:
Decaux Abel Decaux (1869–1943), French classical organist and composer Alain Decaux (1925–2016), French historian Alice Decaux (born 1985), French hurdler Georges Decaux (1930–2015), French cyclist Jacques Decaux (1918–2003), French sport shooter Jean-Claude Decaux (1937–2016), French businessman
De Caux Jean Baptiste de Caux of Blacquetot (1723-1796), French army officer John de Caux, or John de Caleto ( – 1263), Norman-English administrator Len De Caux (1899–1991), American labor activist Louis Victor de Blacquetot de Caux (1773–1845), French army officer
See also Iphigénie Decaux-Milet-Moreau (1778–1862), French painter