Background: Today, sexual education as an instinctive need is a lost circle in the educational system of our society. Objectives: This research was carried out to investigate the effectiveness of sexual education based on mindfulness and Islamic teachings in increasing self-esteem and its related components among female adolescents. Methods: This quasi-experimental research was conducted using a pretest-posttest design with a control group. A total of 60 subjects were selected by cluster random sampling method and assigned into three groups of 20 individuals. The groups were tested and matched before the intervention. Then, the experimental groups were trained using mindfulness and Islamic teaching-based sexual education in eight sessions of 90 min. The Pops' self-esteem questionnaire was used for data collection. The reliability of the questionnaire was obtained between 0.51 and 0.75 and the validity of the questionnaire was confirmed by internal consistency. Results: The mean score was higher in the Islamic teachings group than in the other groups and the mean score of the mindfulness group was higher than that of the control group. Therefore, research hypotheses were confirmed regarding the effectiveness of sexual education based on mindfulness and Islamic teachings in increasing self-esteem and its components. The results showed that mindfulness and Islamic teaching-based sexual education are effective in increasing the components of adolescents' self-esteem. Conclusions: Therefore, it can be concluded that the implementation of sexual education is essential in the curriculum context.