The Women's 4x100 Medley Relay swimming event at the 2009 SEA Games was held on December 13, 2009.
Results edit
Final edit
| Place | Lane | Nation | Swimmers | Time | Notes |
|---|---|---|---|---|---|
| 1 | 4 |  Singapore |
Roanne Ho Shana Lim Quah Ting Wen Tao Li |
4:10.38 | GR |
| 2 |  Malaysia |
4:13.18 | |||
| 3 |  Thailand |
Chavisa Thaveesupsoonthorn Phiangkhwan Pawapotako Natnapa Prommuenwai Natthanan Junkrajang |
4:19.89 |
Note: Results appear to be incomplete (i.e. there were most likely more than 3 teams in the final).