en Aim: The aim of this study was to determine the effect of socioeconomic factors on the constructs of the modified Theory of Planned Behavior (TPB) in relation to reproductive health in adolescents.<br />Methods: A cross-sectional study was conducted among 578 female students aged 12-16 years, recruited through a multistage random cluster sampling method, in Tehran, Iran. A self-administered TPB-based constructed questionnaire was designed and used for data gathering. Multivariate regression analyses were conducted to examine the association between family size, number of siblings, birth rank, and family closeness, source of information, and reproductive health behavior.<br />Findings: The mean age of the participants was 14.1 years. None of the participants obtained a perfect score in relation to reproductive health. In addition, they achieved average scores less than half the rates. Number of siblings, family size, birth rank, mother education and information source were factors associated with TPB the constructs (p<0.001).<br />Conclusion: The results of this study emphasize that Socioeconomic factors can have an effective role in students' sexual and reproductive health behaviors. Reproductive health,Socioeconomic,Theory of planed behavior,Adolescents 21 35 http://hehp.modares.ac.ir/browse.php?a_code=A-5-21791-1&slc_lang=en&sid=4 Fatemeh Darabi Fatemeh Darabi 100319475328460068131 100319475328460068131 Yes Ph.D. in Health Education & Promotion, Assistant Professor, School of Asadabad Medical Sciences, Asadabad, Iran Ph.D. in Health Education & Promotion, Assistant Professor, School of Asadabad Medical Sciences, Asadabad, Iran Mehdi Yaseri Mehdi Yaseri 100319475328460068083 100319475328460068083 No Assistant Professor, Department of Epidemiology and Biostatistics, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran Assistant Professor, Department of Epidemiology and Biostatistics, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran Farideh Khalajabadi Farahani Farideh Khalajabadi Farahani 100319475328460068128 100319475328460068128 No Associate Professor, Department of Health Education and Health Promotion, Faculty of Health, Shiraz University of Medical Sciences, Shiraz, Iran Associate Professor, Department of Health Education and Health Promotion, Faculty of Health, Shiraz University of Medical Sciences, Shiraz, Iran Aghbabak Maheri Aghbabak Maheri 100319475328460068384 100319475328460068384 No Department of Health Education and Promotion, School of Public Health, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran Department of Health Education and Promotion, School of Public Health, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran Mohammad Hossein Kaveh Mohammad Hossein Kaveh 100319475328460068422 100319475328460068422 No Associate Professor, Department of Population, Health and Family Planning, National Institute for Population Research, Tehran, Iran Associate Professor, Department of Population, Health and Family Planning, National Institute for Population Research, Tehran, Iran