William Johnstone may refer to:
Arts William Johnstone (actor) (1908–1996), American actor William Johnstone (artist) (1897–1981), Scottish artist William W. Johnstone (1938–2004), American author Will B. Johnstone (1881–1943), American writer William Borthwick Johnstone (1804–1868), Scottish painter, art collector, and gallery curator
Politics William A. Johnstone (1869–1937), member of the California legislature William Johnstone, 1st Marquess of Annandale (1664–1721), Scottish nobleman Sir William Johnstone, 2nd Baronet (died 1727), member of parliament for Dumfries Burghs and Dumfriesshire Sir William Pulteney, 5th Baronet (1729–1805), born William Johnstone, Scottish member of parliament
Sports Bill Johnstone (footballer, born 1900) (1900–1979), Australian rules footballer for North Melbourne Bill Johnstone (footballer, born 1919) (1919–1976), Australian rules footballer for Collingwood Bill Johnstone (Scottish footballer) (fl. 1920s), Scottish footballer (Clyde, Reading, Arsenal, Oldham Athletic) Billy Johnstone (born 1959), Australian rugby league player William Johnstone (footballer) (1864–1950), Scottish footballer (Third Lanark, Scotland) Rae Johnstone (William Raphael Johnstone, 1905–1964), Australian jockey
Other William Johnstone (VC) (1823–1857), Victoria Cross recipient
See also William Johnston (disambiguation) William Johnson (disambiguation) Bill Johnston (disambiguation) RNLB William and Kate Johnstone, a Barnett-class lifeboat