Nicolas Mahut, French tennis player
Nicolas Pierre Armand Mahut (French pronunciation: ​[nikɔla pjɛʁ aʁmɑ̃ may]; born 21 January 1982) is a French professional tennis player who is a former world No. 1 in doubles.

He is a five-time Grand Slam champion in doubles, having completed the career Grand Slam with victories at the 2015 US Open, 2016 Wimbledon Championships, 2018 French Open, and 2019 Australian Open, all partnering Pierre-Hugues Herbert. The pair also won the 2021 French Open and finished runners-up at the 2015 Australian Open, and Mahut was runner-up at the 2013 French Open and 2019 Wimbledon Championships, with Michaël Llodra and Édouard Roger-Vasselin respectively. Mahut became world No. 1 in doubles on 6 June 2016, holding the top ranking for a total of 39 weeks, and has won 35 doubles titles overall, including the 2019 and 2021 ATP Finals. He has also won seven Masters 1000 titles in doubles.

In singles, Mahut reached a career-high ATP ranking of world No. 37 in May 2014, and has won four tour-level titles. All were on grass courts, where only Roger Federer (19), Andy Murray (8) and Novak Djokovic (6) have won more titles amongst active players. His best Grand Slam result in singles was at the 2016 Wimbledon Championships, where he reached the fourth round. At the 2010 Championships, Mahut was part of the longest match in professional tennis history, against John Isner in the first round. Isner defeated him 70–68 in the fifth set after over 11 hours of play.