The Coral Triangle is a geographical term so named as it refers to a roughly triangular area of the tropical marine waters of Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands and Timor-Leste that contain at least 500 species of reef-building corals in each ecoregion. This region encompasses portions of two biogeographic regions: the Indonesian-Philippines Region, and the Far Southwestern Pacific Region. The Coral Triangle is recognized as the global centre of marine biodiversity and a global priority for conservation. It also called the "Amazon of the seas" and covers 5.7 million square kilometers of ocean waters. Its biological resources sustain the lives of over 120 million people.

The WWF considers the region a top priority for marine conservation, and the organization is addressing the threats it faces through its Coral Triangle Program, launched in 2007.