Infobox last updated on: April 13, 2009.
Guillermo Ignacio Cañas (born November 25, 1977) is an Argentine professional tennis player. He was born in Argentina's capital, Buenos Aires, and named after Argentine tennis star Guillermo Vilas. His highest singles ranking was 8th (June 2005).
Cañas plays a defensive counter-punching game from the baseline, and utilises his retrieving skills in order to frustrate opponents. He uses a double-handed backhand and his favourite surface is clay, but he is adept on hardcourt and grass too.