Timothy Raymond Mathieson (born 1957) is an Australian hairdresser and the former domestic partner of Julia Gillard, the Prime Minister of Australia from 2010 to 2013.

[1] Mathieson entered the public spotlight when he became Gillard's partner in 2006 while she was deputy leader of the Australian Labor Party.

After a hairdressing apprenticeship in suburban Melbourne, he first operated a Shepparton hair salon, then another on the Gold Coast, Queensland.

[6] From January to March 2010, Mathieson focused on the sale of high-rise apartments in Melbourne to international buyers on behalf of a local real estate agency.

[19] In July 2023, Mathieson pleaded guilty to a charge of sexual assault after non-consensually sucking the nipple of a sleeping woman and "latching onto her breast when she tried to fend him off" in March 2022.