Self-determination is an important motive that influences youth development outcomes. Self-determination theory emphasizes the relationship between social context, self-determination, and school educational outcomes. The purpose of this study is to examine the relationship between parental and teacher support, self-determination, career maturity, self-regulated learning, and satisfaction with school. For this study, 1,155 high school students in Korea completed surveys. The results of this study are the following. First, parental support and teacher support affect self-determination. Second, parental support, teacher support, and self-determination influence career maturity, self-regulated learning, and satisfaction with school. On the basis of these findings, this study has implications for the improvement of instructional design methods and management strategies.