2009 WTA Tour Championships – Singles
| Singles | |
|---|---|
| 2009 WTA Tour Championships | |
| Champion | Serena Williams |
| Runner-up | Venus Williams |
| Score | 6–2, 7–6(7–4) |
| Draw | 8 (RR + elimination) |
| Seeds | 8 |
Serena Williams defeated the defending champion, her sister Venus Williams, in the final, 6–2, 7–6(7–4) to win the singles title. It was her second Tour Finals singles title in eight years. Serena remained undefeated throughout the tournament, despite being match point down against Venus in their round robin match.
Caroline Wozniacki and Victoria Azarenka made their debuts at the event.
Dinara Safina and Serena Williams were in the contention of year-end no. 1 ranking. Williams secured the year-end no. 1 ranking for the second time when Safina withdrew from the tournament.