The present study has investigated the relationship of self-efficacy with Tehran city high school student's motivation and taking part in physical activities. The present study methodologically is divided in to 8 kind's hypothesis inductive research approaches, quantitative research strategy, the objectives of the research are descriptive and explaining, and in the end of method and data collection, library resources review and questionnaire. The statistical society of this research consists of all the students of Tehran education districts 14, 6, 3 in 2013 – 2014 academic years. To specify the sample volume Cochran formula was used. Based on this formula the minimum needed volume for this sample for such a research are 203 individuals. The research sample consisted in 400 of Tehran education students (boys and girls) that were selected via stratified cluster sampling method among girls and boys students. The data collection tool was a standard questionnaire. To analyses the research findings, Pearson correlation coefficient and multi-variable regression model in %95 coefficient level were used. The result showed that in the research statistical sample, the subjects have evaluated self-efficacy characteristics higher than average, and evaluated important individuals subscales lower than average. And also specified that there isn’t significant relation between self-efficacy and physical activities and motivation to participate in sports, with %95 confidence level. And also calculated coefficient of determination showed that %2.56 of physical activities variance and %3.68 of motivation to participate in sports is specified via self-efficacy. Article visualizations