The present-day species are native to Southeast Asia and can be found from India and Sri Lanka to southern China, Taiwan, Japan (Boso Peninsula and Oshima Island), and Indonesian islands. Reeves Muntjac has been introduced to England and is now common in some areas there. Inhabiting tropical regions, the deer have no seasonal rut and mating can take place at any time of year. However, this behaviour is retained by populations introduced to temperate countries. Males have short antlers, which can regrow, but they tend to fight for territory with their tusks (downward pointing canine teeth).

Muntjac are of great interest in evolutionary studies because of their dramatic chromosome variations and the recent discovery of several new species. The indian muntiac is the mammal with the lowest recorded chromosome number with the male having a diploid number of 7, the female of only 6 chromosomes. Reeves muntjac (Muntiacus reevesi) in comparison has a diploid number of 46 chromosomes.