Background and Aim: Puberty is a critical period in a woman's life. An important step in strategies designed to promote family and community health is determination of girls health priorities and needs assessment at puberty. This study aims to illustrate the efficiency of need assessment approach in exploring and comparing the viewpoints of mothers, teachers and adolescent girls on girls pubertal health in the context of the school. The findings would help plan better programs aiming at changing the heatlh behaviour of girls.Materials and Methods: In this qualitative study 12 guidance school girls, 12 mothers and 7 teachers from District 6, Tehran were selected to participate in focus group discussions to prepare a semi-structured questionnaire. The content analysis method was used to analyze the results of discussions with the participants and complete the final questionnaire. Results: The findings reveal the efficiency of the need assessment approach as follows: a wide discrepancy in viewpoints of the three study groups was identified in terms of pubertal health priorities, health needs of the girls, and pubertal health educational priorities. In addition, the results show a lack of a notion of comprehensive sex health education in the school. Conclusion: The findings indicate that the need assessment approach is a useful way to plan and implement appropriate health education programs for adolescent girls.