The black-headed weaver (Ploceus melanocephalus), also known as yellow-backed weaver, is a species of bird in the family Ploceidae. It is a resident breeder in damp areas in tropical Africa. The black-headed weaver was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the binomial name Loxia melanocephala. He specified the type locality as Guinea. Linnaeus based his account on the "Gamboa Groasbeak" that had been described and illustrated in 1750 by the English naturalist Eleazar Albin in his book A Natural History of Birds. Albin had sketched a live specimen belonging to the Duke of Chandos at his country house, Cannons, which was located about 11 mi (18 km) northwest of London near Edgware. The specific epithet melanocephalus, melanocephala combines the Ancient Greek μελας/melas, μελανος/melanos meaning "black" with -κεφαλος/-kephalos meaning "-headed". The black-headed weaver is now one of 67 species placed in the genus Ploceus that was introduced in 1816 by the French naturalist Georges Cuvier.
Five subspecies are recognised: