Thassha Vitayaviroj (; 10 June 1986) is a former professional Thai tennis player.
Vitayaviroj has career-high WTA rankings of 439 in singles, achieved on 2 May 2005, and 320 in doubles, set on 24 April 2006. She won five doubles titles on the ITF Women's Circuit. Her only WTA Tour main-draw appearance came at the 2002 Volvo Women's Open, where she partnered with Montinee Tangphong in the doubles event.
Playing for Thailand Fed Cup team, Vitayaviroj has a winâÂÂloss record of 0âÂÂ1.