en Medicine پژوهشي Research <div style="text-align: justify;"><strong>Background and objectives</strong><strong>:</strong> The aim of this study was to identify the factors affecting early onset of puberty in primary school girls.<br> <strong>Methods:</strong> This study was done on 687 primary school girls living in Kordkuy, Iran. The sample size was calculated using the Krejcie-Morgan sample size determination&nbsp;<em>table</em>. Data were collected using interviews and a researcher-made questionnaire. The collected data were analyzed by SPSS (version 22) using the Chi-square test, Spearman&#39;s correlation coefficient and exploratory factor analysis.<br> <strong>Results:</strong> There was a strong positive correlation between level of awareness of girls and physical and psychosocial changes. Overweight, type of diet and watching satellite films were associated with the earlier onset of puberty.<br> <strong>Conclusions: </strong>Based on the results of our study, raising awareness of families about the harmful effects of satellite films and unhealthy eating habits may have a significant role in physical and psychosocial health of girls.</div> Age of puberty, health, students, girls 45 49 http://jcbr.goums.ac.ir/browse.php?a_code=A-10-85-2&slc_lang=en&sid=1 Negin Jabbari نگین جباری 10031947532846001590 10031947532846001590 No Department of Educational Management, School of Humanities, Islamic Azad University, Gorgan Branch, Gorgan, Iran Shirin Karimitaleghani شیرین کریمی طالقانی 10031947532846001591 10031947532846001591 Yes Department of Educational Management, School of Humanities, Islamic Azad University, Gorgan Branch, Gorgan, Iran Masoumeh Mazandarani معصومه مازندرانی 10031947532846001592 10031947532846001592 No Department of Educational Management, School of Humanities, Islamic Azad University, Gorgan Branch, Gorgan, Iran