Acanthopagrus schlegelii, the blackhead seabream, black porgy or black seabream, is a species of marine ray-finned fish belonging to the family Sparidae, the seabreams and porgies. This species is found in the Western Pacific Ocean. The blackhead seabream is an important species in commercial fisheries, particularly in Vietnam.

Taxonomy Acanthopagrus schlegelii was first formally described as Chrysophrys schlegelii in 1854 by the Dutch physician, herpetologist and ichthyologist Pieter Bleeker with its type locality given as Nagasaki. Some workers have suggested that there are two species within this taxon, A. schlegelii and A. czerskii, while others treat these as subspecies within the same species. Some authorities classify the genus Acanthopagrus in the subfamily Sparinae, but the 5th edition of Fishes of the World does not recognise subfamilies within the Sparidae.

Etymology Acanthopagrus schlegelii has a specific name that honours the German ornithologist and herpetologist Hermann Schlegel who co-wrote Fauna Japonica with Coenraad Jacob Temminck, a book Bleeker often cited. The subspecies A. s. czerskii honours the ornithologists Alexander Ivanovich Czerski, the son of Jan Czerski, a celebrated Polish geologist, naturalist and explorer, who collected the type specimen.

Acanthopagrus schlegelii has its dorsal fin supported by 11 or 12 spines and 11 soft rays while the anal fin contains 3 spines and 8 soft rays.