|The aim of the study was to investigate the various effects of after-school physical activities on the degree of students` physical self-efficacy and of their satisfaction in school life. The effects were assessed through questionnaires from 600 students at four high and middle schools in Seoul. Data were analyzed using the independent t-test model, one-way analysis of variance (ANOVA), and the Duncan test was applied as a posteriori test. The following is a summary of the main findings. First, students who participated in after-school extracurricular activities reported higher levels of physical self efficacy (PSE) and school life satisfaction. Second, individual activities facilitated increases in students perceived levels of PSE, satisfaction with school life in class, and their relationships with peers than group activities. Third, positive reinforcements of the findings were evident through a prolonged participation in the after-school extracurricular activities, Fourth, it was observed that students felt more confident and satisfied with noted improvements in their ability of physical expression and their level of PSE, The results of this research indicate the importance of after-school extracurricular activities and highlight the benefits of physical activities on students lives.