A tiny, colorful seed-eating waxbill with grayish underparts, an olive-green back, and a scarlet rump and upper tail. The male has a black throat patch which the female lacks. Pairs and small groups eat grass and small insects in open areas adjacent to forest, thickets, and garden cover. The species is often detected by its simple soft, plaintive “swee-swee” and “seeet” calls. The Yellow-bellied Waxbill strongly resembles the Swee Waxbill, but its belly is washed buff, the male lacks a black throat, and their ranges do not overlap.