Joel Theissen (born 12 August 1986 in Windsor, New South Wales) is an Australian footballer who last played for GPS Portland Phoenix in the USL Premier Development League.
A left-sided midfielder or defender, Thiessen attended the Australian Institute of Sport, and played with former NSL side Newcastle United, before catching the eye of Sydney FC head coach Terry Butcher.
In March 2008 Thiessen re-located to the United States to attend college at the University of New Mexico.
After failing to be cleared by the NCAA clearinghouse he moved on to the University of Rio Grande in the NAIA.
He played with the Cape Cod Crusaders in the USL Premier Development League during his 2008 collegiate off-season.