John Barton Hack (2 July 1805 – 4 October 1884) was an early settler in South Australia; a prominent farmer, businessman and public figure. He lost his fortune in the financial crisis of 1840 and despite his best efforts, never regained anything like his former influence and prosperity. His son Theodore Hack, younger brother Stephen Hack and nephew Wilton Hack were all figures of some significance in the history of the Colony.