Objectives: Physical activity is considered as an essential component of a woman’s ability to maintain or improve her level of wellness. Nevertheless, women, particularly young girls, usually pay less attention to health-promoting behaviors such as regular physical activity. Given the significance of physical activity in woman’ health status, the present study aimed to determine the influence of such activity and body mass index (BMI), especially on menstrual characteristics and menarche age among young females according to their socioeconomic status (SES). Materials and Methods: Data collection included two parts. First, a cross-sectional study was conducted on 1000 healthy and young females aged 11-28 years and standardized self-reporting questionnaires were used to obtain relevant information. Then, purposive sampling technique was utilized to compare the information pertinent to physically active and inactive females or those with sedentary behavior. The data were later analyzed using the chi-square test by SPSS 16. Results: Based on the results, the majority of the young female population were physically inactive and only 121 women (12.1%) enjoyed exercising at least for 30 minutes three times a week or more. In addition, there was a significant correlation between BMI, SES, and physical activity involvement. The cycle length, the regularity of periods, and the severity of dysmenorrhea exhibited a positive association with involvement in physical activity. Conclusions: Overall, physical activity had a positive influence on menstrual characteristics in young females. Therefore, it is important to educate women for regular physical activity in order to modify or reduce menstrual cycle disturbances.