John Millar may refer to:
- John Millar (philosopher) (1735–1801), Scottish philosopher and historian
- John Millar, Lord Craighill (1817–1888), Scottish judge
- John A. Millar (1855–1915), New Zealand politician
- John Millar (Canadian politician) (1866–1950)
- John Millar (footballer, born 1923) (1923–1986), Scottish footballer
- John Millar (footballer, born 1927) (1927–1991), Scottish footballer
- John Millar (footballer, born 1966), Scottish footballer (Chelsea, Blackburn Rovers, Heart of Midlothian)
- John Millar (rugby union), Scottish rugby union player
- John Millar, Scottish confectioner, see Millar McCowan
- John Millar, American spiritual head of Elohim City, Oklahoma
- Sandy Millar (John Alexander Kirkpatrick Millar, born 1939), Anglican bishop
- John Millar, musician in The Hush Now