Alexander Johnston
Alexander Johnston may refer to:
- Alexander Johnston (businessman) (1774–1864), Scottish mill owner
 - Alexander Johnston (1775–1849), British colonial official and orientalist in Ceylon
 - Alexander Johnston (Scottish politician) (1790–1844)
 - Alexander Keith Johnston (1804–1871), Scottish geographer
 - Alexander Robert Johnston (1812–1888), British colonial official
 - Alexander Johnston (artist) (1816–1891), Scottish painter
 - Alexander Keith Johnston (1844–1879), Scottish geographer
 - Alexander Johnston (footballer) (1881–1917), Scottish footballer
 - Alexander Johnston (historian) (died 1889), American historian
 - Alexander Johnston (Canadian politician) (1867–1951), Canadian journalist, civil servant and politician
 - Alexander Johnston (Ontario politician), Canadian politician, Ontario MPP
 - Alexander Johnston (British Army officer) (1884–1952), Hampshire cricketer and army officer
 - Alexander Johnston (civil servant) (1905–1994), Scottish civil servant
 - Alexander W. Johnston (died 1932), Member of the Legislative Council of Samoa
 - Alex Johnston (Australian rules footballer) (1881–1965), Australian rules footballer
 - Alex Johnston (rugby league) (born 1995), Australian professional rugby league footballer