The Mekong Delta (Vietnamese: Đồng bằng Sông Cửu Long “Nine Dragon river delta”) is the region in southwestern Vietnam where the Mekong River approaches and empties into the sea through a network of distributaries. The Mekong delta region encompasses a large portion of southwestern Vietnam of 39,000 square kilometres (15,000 sq mi). The size of the area covered by water depends on the season.

The Mekong Delta has recently been dubbed as a 'biological treasure trove'. Over 10,000 new species have been discovered in previously unexplored areas of Mekong Delta, including a species of rat thought to be extinct.