Nicolás Barrientos (Spanish pronunciation: [nikoˈlaz βaˈrjentos]; born 24 April 1987) is a Colombian professional tennis player competing mainly on the ATP Challenger Tour both in singles and doubles. Barrientos reached his highest ATP singles ranking of world No. 237 on 21 September 2015 and his highest ATP doubles ranking of world No. 61 on 24 October 2022. Barrientos also made his first appearance on an ATP World Tour in July 2013 when he lost in the first round of 2013 Claro Open Colombia against Ruben Bemelmans.