The 2005 US Open was the fourth and final Grand Slam of 2005. It was held between August 29, 2005, and September 11, 2005.

Roger Federer was successful in defending his 2004 title, defeating Andre Agassi in the final. Svetlana Kuznetsova was unsuccessful in her title defense, losing in the first round against compatriot Ekaterina Bychkova. Kim Clijsters won her first Grand Slam title after four previous Grand Slam final losses. It was the first of three US Open titles for Clijsters, also winning in 2009 and 2010. This was the first time that future US Open (Tennis) champion Andy Murray was featured in the tournament.

Roger Federer defeating Andre Agassi, 6–3, 2–6, 7–6(1), 6–1

Kim Clijsters defeating Mary Pierce, 6–3, 6–1

Bob Bryan / Mike Bryan defeating Jonas Björkman / Max Mirnyi, 6–1, 6–4

Lisa Raymond / Samantha Stosur defeating Elena Dementieva / Flavia Pennetta, 6–2, 5–7, 6–3

Daniela Hantuchová / Mahesh Bhupathi defeating Katarina Srebotnik / Nenad Zimonjić, 6–4, 6–2

Ryan Sweeting defeating Jérémy Chardy, 6–4, 6–4