Kim Clijsters defeated Caroline Wozniacki in the final, 7–5, 6–3 to win the women's singles tennis title at the 2009 US Open.

It was only Clijsters' third tournament since giving birth and coming out of retirement, and has been described as one of the most stunning championship runs in major history.

[1] Serena Williams was the defending champion, but was defeated in the semifinals by Clijsters.

A foot fault was called for Williams at the end of the second set, producing two match points for Clijsters.

[2] Svetlana Kuznetsova's loss in the fourth round guaranteed a first time major finalist from the top half of the draw.