The orange-bellied flowerpecker (Dicaeum trigonostigma) is a species of bird in the family Dicaeidae.

It is found in Bangladesh, Brunei,Indonesia, Malaysia, Myanmar, the Philippines, Singapore, and Thailand.

Male is distinctive, and shows slaty-blue upperparts (crown/nape/wings/tail) except for a large triangular orange patch on the mantle.

Female is much duller, and is mostly drab olive brown overall, except for its pale orange rump and yellow belly.

However, melanostigma continued to be cited in various lists (Howard and Moore, Complete Checklist of the Birds of the World (1980, 1991)), as well as on websites which list birds common to Thailand and the surrounding region, thus possibly allowing for the inadvertent description of this name should any published reference to it accompany a picture of an orange-bellied flowerpecker.