Data on third permanent molar eruption was obtained from a cross-sectional study of 1343 African and 1092 Asian students aged 13-23 years attending various schools in Nairobi and the University of Nairobi, Kenya. Africans are significantly ahead of the Asians in third molar emergence. As seen from the median age of eruption, in Africans mandibular molars emerge at 17.6-18.3 years followed by the maxillary at 18.5-18.9 years, while in the Asians mandibular molars emerge at 19.9-20.3 years and maxillary at 20.7-21.0 years. African females appear to be earlier than the males in median age of eruption by 0.3-0.4 years, while the Asian females tend to be later than the males by about 0.3 years, but these differences are not significant. Third molar emergence starts earlier in Africans at 13 years of age, and by 18.5 years 50% of Africans have all four molars present. In the Asians, third molar emergence begins at about 15 years and by 21.5 years 50% have all four molars present.