John Thomas Diamond MBE (21 June 1912 – 20 February 2001) was an amateur New Zealand historian and archaeologist.

Diamond became interested in history after finding Māori artifacts on a farm near Warkworth where he was working.

[2] In the 1986 Queen's Birthday Honours, Diamond was appointed a Member of the Order of the British Empire, for services to archaeology.

[3] In December 1999, he received a Waitakere City Council Millennium Medal for his services to the community and heritage of the west.

[1] Diamond left his collection of papers, research notes, photographs and slides to Waitakere Libraries.