2015 US Open – Men's singles

Novak Djokovic defeated Roger Federer in the final, 6–4, 5–7, 6–4, 6–4 to win the men's singles tennis title at the 2015 US Open. It was his second US Open title and tenth major title overall. By reaching the final, Djokovic became the third man to reach all four major finals in the same year in the Open Era, after Rod Laver and Federer. The final was also a rematch of the Cincinnati final three weeks earlier, and a rematch of the 2007 US Open final eight years prior, both won by Federer.

Marin Čilić was the defending champion, but lost to Djokovic in the semifinals.

This marked the first time since the 2010 US Open that Andy Murray lost before the quarterfinals of a major, losing to Kevin Anderson in the fourth round: a streak of 18 consecutive major quarterfinals (not counting the 2013 French Open, which he missed due to injury). This also marked the first time Rafael Nadal failed to win a major and reach any major semifinal since 2004, having lost in the third round to Fabio Fognini. The loss also ended Nadal's record 10-year streak of winning at least one major, and leaving him one year short of the record 11-year streak of reaching at least one major final (a record shared by Ivan Lendl and Pete Sampras).

This marked the last professional appearance of former world No. 7 Mardy Fish and the last US Open appearances of 2001 champion and former world No. 1 Lleyton Hewitt, and former world No. 2 Tommy Haas.