Irwin Thomas (born Irwin Thomas Whittridge on 6 January 1971) is an American-born Australian singer-songwriter and guitarist. He performed professionally using the stage name of Jack Jones when he was the lead vocalist-guitarist in band Southern Sons (1990–96) and again with Rick Price. His other bands and collaborations include Electric Mary, She Said Yes and Ahmet Zappa. He released his solo album debut in 2002, ‘The Evolution Of Irwin Thomas’, and toured as a support act to Matchbox Twenty.

Irwin Thomas Whittridge was born in Manhattan, New York City. His father Private Irwin Thomas Whittridge Snr, went under the stage name of Jack Goode (born, c.1909 – June 1971), was a Broadway performer. His mother, Renalda Whittridge (née Green), was an Australian-born folk singer and dancer; she returned to Australia in 1980, with her son. He was later known as Jack Thomas Whittridge Jones.