The purpose of this study was to understand what influence Self-Regulation has on Emotion and School Life Satisfaction of adolescents participation in after-school sport activities. The instrument for data collection was a questionnaire in which Self-Regulation Scale as identified by Miller(2000), translated by Heo(2004), Emotion Scale as amended and supplemented by Yoo & Kim(2002), School Life Satisfaction Scale as identified by Lim(1993), translated by An(2006). 270 subjects were selected from the adolescents participation in after-school sport activities in the gyungki by the stratified cluster sampling method. Among these selected subjects, 252 responded, and data analyses consisted of employing frequency analysis, factor analysis, one-way ANOVA, Multiple correlation, Multiple Regression Analysis using SPSS/PC+ version 14.0. The following results were obtained: 1. It was found that self-regulation of adolescents participation in sports activities has an influence on emotion. 2. It was found that self-regulation of adolescents participation in sports activities has an influence on school life satisfaction. 3. It was found that emotion of adolescents participation in sports activities has an influence on school life satisfaction.