John Thomas Gannon (1830 – 5 August 1887) was a politician and solicitor in New South Wales, Australia.
He was born in Sydney in around 1830,[1][a] the second child of convict James Gannon and his wife Mary née Phelps.
A younger brother Michael would later be a member of the Queensland Legislative Assembly.
[6][7] He was elected to the New South Wales Legislative Assembly for Argyle at the by-election in 1881, serving until he resigned in March 1885.
[9] In 1897 he ostensibly went on holiday to Fiji, but in fact fled to the United States after misappropriating nearly £15,000 of client's money.