The Pin-tailed Whydah is around 13 cm in length. The male in breeding plumage has a long tail, of up to 20 cm in length, with the bird having a black back and crown.
The wings are dark brown with white patches.
The rest of the plumage is white. The bill is a red/orange colour.
The female and non-breeding male both have white underparts with fawn coloured flanks.
The face is fawn and black with a black moustachial stripe.
The upper part of the plumage is a streaked brown pattern. Both male and female have red/orange bills.
The Pin-tailed Whydah is polygynous and the males have several females in his group. This whydah is a host-specific brood parasite and the female lays her eggs in the nest of a waxbill.
The common waxbill being the primary host and the orange-breasted waxbill being the secondary host. Unlike other brood parasite’s, the pin-tailed whydah does not remove the host's eggs when laying its own and the parasite chick does not kill its host “sibling”.
The Pin-tailed Whydah female will lay 3 to 4 eggs in the host's nest. When the chicks hatch, they mimic the gape pattern of the host fledging.