The birth of twins, and especially multiple sirehood dizygotic twins, is very rare in Old World monkeys, the only previous record is of a captive rhesus macaque (Macaca mulatta). Here, we report a case of multiple sirehood dizygotic twins among the 114 newborns (0.88%) recorded in a population of semi-wild stump-tailed macaques (M. arctoides) in the Khao Krapuk Khao Taomor (KKP) Non-hunting Area, Thailand. Using ten microsatellite markers, we determined that the infants were sired by different adult males, thus suggesting the multiple sirehood. Since the association between twin birth and high frequencies of supernumerary (> 2) nipples was reported in Formosan macaques (M. cyclopis) in Taiwan, the supernumerary nipples were observed in KKP macaques. Of the 332 monkeys counted, 22% of the adults and subadults in the KKP population, and 33.3% of females in the focus (Ting) group, had supernumerary nipples. However, both twins and their mother had two ordinary nipples. Thus, we conclude that it has no association between the occurrence of supernumerary nipples and twin births in stump-tailed macaques.