The Mangrove Pitta was first described by German ornithologist Hermann Schlegel in 1863.Its species name is derived from the Ancient Greek words mega- "large", and rhynchos "beak". It forms a superspecies with the Indian Pitta (P. brachyura), Fairy Pitta (P. nympha) and Blue-winged Pitta (P. moluccensis). Alternate common names include: Larger Blue-winged/Malay Pitta, Brève des palétuviers (in French), Große Blauflügelpitta (in German), and Pita de Manglar (in Spanish).There are no recognized subspecies.
Measuring 180–210 mm (7.1–8.3 in) in length, the Mangrove Pitta has a black head with a buff-coloured crown, white chin and buff underparts. The shoulders and mantle are greenish and the vent is reddish. Juveniles have similar patterned plumage but are duller. It resembles the Blue-winged Pitta but can be distinguished by its much heavier bill. Its call, transcribed as wieuw-wieuw has been noted to be "more slurred" than the Blue-winged Pitta.