Objectives: The objectives of our study were to determine the mean age of onset of thelarche and menarche, to determine the ages of each stage of puberty and to investigate if there are any ethnic differences in these ages amongst female adolescents in Kuala Lumpur, Malaysia. Methods: This was a cross-sectional study involving three secondary schools in Cheras, Kuala Lumpur. A total of 730 students were recruited via stratified random sampling. Self-administered survey forms on menstruation and puberty were used. Results: Out of 730 recruited respondents, 385 (52.74%) completed the survey and informed consents were obtained from their parents/legal guardians. Our respondents’ ages ranged between 13 to 17 years old with the median (IQR) age of 14.00(2.00) years. With regards to ethnicity, 329 (85.50%) were Malay, 46 (11.90%) were Chinese, 9 (2.30%) were Indian and 1(0.30%) was a Bajau. The mean age for breast development (thelarche) and menarche were 11.72 ±1.10 and 11.97±1.11 years respectively. The majority, 363 (94.30%), out of 385 respondents had attained menarche. There appeared to be a later onset of puberty amongst Malays comparatively. Conclusion: The mean ages of pubertal onset and menarche amongst female adolescents in the Cheras area are similar to those reported worldwide.