Background & Aims Adolescence is a period in which people are at risk of engaging in many health-threatening behaviors such as increased food intake, decreased physical activity, and increased developmental vulnerability which can be a threat to their future health. Counseling and changing their unhealthy behaviors can improve various aspects of their health, including mental and physical health. This study aims to determine the relationship between mothers' self-efficacy and health-promoting behaviors of their adolescent girls in Shiraz, Iran. Materials & Methods In this study, participants were 384 high school female students (second term) and their mothers in Shiraz city in 2018. Mothers completed Sherer’s General Self-efficacy Scale and their girls completed Walker's Health-Promoting Lifestyle Profile II (HPLPII) questionnaire. Pearson or Spearman correlation test and t-test were used for statistical analysis in SPSS software, version 22. Results The mean HPLPII score of girls was 169.29±15.97. The mothers' mean self-efficacy score was 46.66±5.77. The results of Pearson's correlation test showed the direct and significant correlation of mothers' self-efficacy scores with health-promoting behaviors of girls and its domains (r=0.556, P<0.05). Conclusion There is a direct significant relationship between mothers' self-efficacy and health-promoting behaviors of their daughters. Considering the importance of health-promoting behaviors and the effect of self-efficacy and living conditions on these behaviors, it is needed to develop strategies to improve people's lifestyle and healthy behaviors. Policy makers in the health system are recommended to promote self-efficacy of mothers by using cultural and educational programs.