Background: Age of menarche marks important points of physical and cultural maturation in adolescents. It has been known that early age at menarche is correlated with diabetes mellitus, breast cancer, elevated adult BMI, metabolic syndrome. Many of these diseases are lifestyle diseases and are severely debilitating to the quality of life. Such easily preventable diseases need a thorough research in order to understand the relation between early menarche and its correlates in adolescent girls. Objectives: To study the mean age of menarche and its correlates among adolescent Omani girls. Methods: A cross- sectional study was done in the grade 9 and 10 girls of Omani high schools of Sohar. A pre validated structured questionnaire was used for data collection on correlates of menarche and body mass index was measured. Data was analyzed using SPSS. Results: The mean age of menarche of study population of was 12.63 years ? 1.057 SD. Age of menarche was found to be inversely associated with BMI (p<0.01). Girls who had painful menses had a slightly lower mean age of menarche compared to those who did not have painful menses (p<0.01). However, it did not have any correlation with regularity of menses and heavy bleeding during menses. Undernourished girls were more likely to have irregular menses (p <0.05). Conclusion: The study supports the worldwide secular trend of decreasing mean age of menarche. The age of menarche of study population was found to have an inverse relation with their BMI. Dysmenorrhea was associated with lower mean age of menarche.