John Cairns
John Cairns may refer to:
- John Cairns (biochemist), biochemist who first demonstrated the structure and replication of the E. coli genome
- John Cairns (cricketer), English cricketer
- John Cairns (politician), British politician, MP for Morpeth
- John Cairns (1818–1892), Scottish divine and writer
- John Cairns (1857–1922), United Presbyterian Church minister, writer and biographer
- John Cairns (born 1942), former moderator of the general assembly of the Church of Scotland
- John Cairns (footballer), Scottish football forward