2009 French Open – Men's singles

Roger Federer defeated Robin Söderling in the final, 6–1, 7–6^(7–1), 6–4 to win the men's singles tennis title at the 2009 French Open. It was his first French Open title and 14th major title overall, completing the career Grand Slam and equaling Pete Sampras' all-time record of men's singles major titles. It was Federer's fourth consecutive French Open final, having lost the previous three to Rafael Nadal. Söderling was the first Swedish major finalist since Thomas Johansson at the 2002 Australian Open.

Nadal was the four-time defending champion, but was defeated in the fourth round by Söderling. It was Nadal's first defeat at the French Open, having won the title in all four of his previous appearances since debuting in 2005 and winning his first 31 matches. His loss guaranteed a first-time French Open champion. In the ten-year span from 2005 to 2014, this was the only edition of the French Open not won by Nadal. Söderling's victory is widely regarded as one of the biggest upsets in tennis history.

Until the 2016 Wimbledon Championships, this was the last major where Novak Djokovic failed to reach the quarterfinals. He lost to Philipp Kohlschreiber in the third round.

This was the last main draw major appearance for 2004 champion and former world No. 5 Gastón Gaudio.