The purpose of this study is to analyze the effectiveness of participating in after-school programs. In order to achieve the purpose, the study is conducted by using follow-up data from the Korean Education Longitudinal Study and applying sets of linear growth models. Using these models, the study analyzes whether or not students' participations and persistent engagements in after-school programs (ASP) influence their school lives, academic performances, and expenses on private tutoring. Results show that from Grade 8 to 10, the participation in ASPs failed to show any significant effects on the academic performances. The students who attended ASPs, however, experienced better relationship with teachers and friends and spent less money on private tutoring as grade level goes up. The persistence of participation showed significant initial differences in academic performances, but it has little effect on students' school lives in general, their academic performances, and expenses on private tutoring.