Background & Objectives: Adolescence is an important and crucial period associated with physical, emotional and evolutional changes making a teenage ready for adulthood. Impact of these changes determines teenager health behaviors in adulthood. Therefore, investigating health improving behaviors and planing to take appropriate actions to maintain and improve health level of this group are necessary. This study aimed to determine health improving behaviors in students of Qazvin secondary schools. Methods: For present descriptive- analytical study, 513 secondary students were selected using claster sampling metho. Data were gathered through demographic data questionaier and standard questionnaire of health improving behaviors (HPLHP). Data were analyzed by SPSS win/16 using descriptive-analytical statistics chi-square and logestics grading analysis. Results: Research results showed that obtained total score for health improving behaviors in teenagers was fair and boys had higher score than the girls. Boys had significantly better levels in the areas of nutrition ((p=0.040) and physical activity (p=0.001) than the girls. No significant differences were found for other areas. Conclusion: Present study showed that heath promoting behaviors of teenagers was in fair level. Therefore, providing proper health and educational services and in some cases consultant services to teenagers and their families should be considered.