Background & Aim: Obesity is increasing dramatically world-wide not only in adults, but also in children and adolescents. Nutritional and physical activity behaviors are related to the prevalence of obesity. Determining adolescents' behavioral patterns is important in preventing and adjusting this healthy problem. This study was carried out to assess lifestyle behaviors among girl adolescents and to determine the association between these behaviors and perceived parental lifestyle behaviors.

Methods & Materials: In this cross-sectional study, 270 students were selected using multistage random sampling from girls' schools in the areas covered by Tehran University of Medical Sciences. Data were collected using a questionnaire. Descriptive and analytical tests were used to analyze the data.

Results: Results showed that the mean age was 13.3 (10.7-16) years. Most of the adolescents' had normal limits of BMI. Only 9.2% of adolescents had optimal dietary behavior and 4.3% were physically active. There was not significant relationship between their nutritional behavior and their perceptions about parents' lifestyle. BMI and parents economic status was related to nutritional behaviors significantly. Physical activity was statistically related to BMI and mothers' education.

Conclusion: This study showed that the adolescents' nutritional and physical activity behaviors were not healthy. Some factors are related to the adolescents' healthy behavior. Teaching healthy behaviors and defining healthy behavioral patterns for adolescent are necessary.