The yellow-crowned bishop (Euplectes afer) is a species of passerine bird in the family Ploceidae native to Africa south of the Sahara. It is highly sexually dimorphic in its breeding season, during which the male adopts a distinctive yellow and black plumage, contrasting with the female's predominantly brown coloration. Three subspecies are recognised.
The yellow-crowned bishop is 95 to 105 mm in length. During the breeding season it is sexually dimorphic — that is, the observable characteristics of the males become more apparent. During the breeding season, the male has distinctive golden yellow and black plumage. The bill of both sexes is short and conical. The color of the male's bill is black during breeding season; by contrast, during non-breeding season, the male's bill is horn in color, as is the female's. The legs and feet are pinkish brown. The male has a black lower face, throat, breast and belly, a wide black collar on the back of the neck, and a brilliant yellow crown, forehead, and hindcrown. There is a yellow patch on the shoulder, and the rump and back are yellow. The wings and tail are brown. During non-breeding seasons the male plumage looks like the female plumage. The female yellow-crowned bishop has pale brown upperparts, with darker streaking. The eyebrow is paler and the underparts are off-white with fine dark streaks on the breast and flanks.
The male in breeding plumage resembles the yellow bishop, but the latter species is larger and lacks the yellow crown. Non-breeding males and females can be confused with those of the southern red bishop, but have white rather than the buff-coloured underparts of the latter.