John Campbell (4 July 1857 – 4 August 1942) was a Scottish architect, responsible for many government buildings in New Zealand.
Born in Scotland, he travelled to New Zealand in 1882 after training in Glasgow under John Gordon. From 1883 to his retirement in 1922 he worked for the government, holding the title of Government Architect from 1909 onwards. He is most widely known for post offices, including those of Auckland and Wellington and two other designs reproduced widely across the country.
In New Zealand he first lived and worked in Dunedin. While there he was responsible for the 1896 prison, later also a Police Station, in the Queen Anne manner and reminiscent of Norman Shaw's New Scotland Yard, and for the Dunedin Law Courts building, an adaptation of an earlier design for a railway station whose plan is a precursor of Campbell's design for the New Zealand parliament building in Wellington.