Self-determination, which has recently been emphasized with the growing interest in the culture of the disabled, is an important factor that young people with developmental disabilities must acquire in order to lead a qualitative life at home, school, and community. This study starts with the premise that art provides an opportunity for adolescents with developmental disabilities to choose their own creative process and reveal their voices through art works. Therefore, the purpose of this study is to analyze in-depth the behavior and experiences of adolescents with developmental disabilities participating in art education programs applying the self-determination model. This art education program applying a self-determination model was developed using a qualitative case study methodology and the participants' experiences were analyzed in-depth by applying it to six adolescents with developmental disabilities. As a result of data analysis, four topics were derived on the change in self-determination of adolescents with developmental disabilities through art activities. First, they experienced the expansion of aesthetic curiosity and expression based on his preferences and interests without external interference. Second, goal setting and plan for achieving goals were implemented and expressed as goal setting, self-directed, and receptive attitude. Third, self-satisfaction and problem-solving skills were shown based on their strengths in the task performance process. Fourth, it could be seen that in the process of expressing based on one's interest and experience, connection with one's life and active participation took place. This study is meaningful as a basic study in that it derived key elements that can structure art education programs to improve self-determination of adolescents with developmental disabilities.