Larnach may refer to:
People Guy Larnach-Nevill, 4th Marquess of Abergavenny (1883–1954), British peer James Walker Larnach (1849–1919), owner of Jeddah, winner of the 1898 Derby John Larnach (1805–1869), father of William Larnach and overseer for James Mudie Mike Larnach (born 1952), Scottish footballer Trevor Larnach (born 1997), American baseball player William Larnach (1833–1898), New Zealand businessman and politician known for building Larnach Castle
Other uses Larnach Castle, in Dunedin, New Zealand
See also Tom Larnach-Jones, co-founder of the Australian record label Trifekta