Objective To investigate the distribution patterns of relative forefoot skeletal dimensions in extant primates.    Methods A total of 163 specimens (85 males and 78 females) from 12 extant primate genera were examined. The metatarsal length and proximal phalangeal length were analyzed by principal component analysis (PCA) and mean-based correspondence analysis for assessing the relative length distribution of the first to fifth metatarsals and proximal phalanges across different primate genera. Additionally, sex-based differences in the relative metatarsal and proximal phalangeal lengths were compared between chimpanzees and modern humans.    Results Among extant primates, the first metatarsal was significantly shorter than the other metatarsals. In non-human primates, the first proximal phalanx was notably shorter than the other proximal phalanges, whereas in modern humans, the first proximal phalanx was distinctly longer than the others. PCA results demonstrated that the relative lengths of metatarsals and metatarso-phalangeal segments provided strong taxonomic differentiation among extant primates. The result of the mean-based correspondence analysis showed that the third and fourth phalangeal length/metatarsal length in modern humans were significantly lower than those of non-human primates. Apart from the second/fifth and fourth/fifth phalangeal length in chimpanzees, as well as the second/third metatarsal length in modern humans, no significant sex differences were observed in the lengthratios of most metatarsals and proximal phalanges.    Conclusion The considerable variation in relative lengths of the forefoot skeletal elements among extant primates provides new insights into the evolutionary trajectory and functional adaptations of the primate foot.