Nicolás Barrientos (Spanish pronunciation: [nikoˈlas βaˈrjentos];[a] born 24 April 1987) is a Colombian professional tennis player who specializes in doubles.

[1] Barrientos has won one ATP Tour doubles title at the 2024 Rio Open with Rafael Matos.

Barrientos 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.

[3] In 2024, Barrientos began a partnership with Rafael Matos which started to produce good results.

[6][1] Partnering Skander Mansouri, he was runner-up at the 2024 Almaty Open, losing to Rithvik Choudary Bollipalli and Arjun Kadhe in the final.