William Cowan

William Cowan may refer to:


 * William Cowan (footballer) (1900–1979), English footballer
 * William Cowan (fur trader) (1818–1902), of the Hudson's Bay Company
 * William Cowan (politician) (1825–1899), reeve of North Gower Township, Ontario
 * William Henry Cowan (1862–1932), Scottish politician
 * W. Maxwell Cowan (William Maxwell Cowan, 1931–2002), South African neuroscientist
 * Mo Cowan (William Maurice Cowan, born 1969), U.S. Senator from Massachusetts
 * William Cowan (engineer) (1823–1898)
 * Bill Cowan (born 1943), security expert
 * Bill Cowan (tennis) (born 1959), Canadian tennis player
 * Billy Cowan (born 1938), retired baseball player
 * Billy Cowan (footballer) (1896–?), Scottish footballer