Studio STEM adopts a design studio model to provide middle school youth with the opportunity to work with peers and college student facilitators after school in a relaxed, non-threatening, collaborative environment. Two informal learning educators guided overall instruction and pacing, but youth directed their own step-by-step activities by appropriating available resources based on their understanding of presented science and engineering concepts and design problems. We investigated how Studio STEM impacted youth's motivation, beliefs, and identification with engineering, science, and computer science. We documented that the Studio STEM environment supported students' empowerment, highlighted the usefulness of the content, allowed students to feel successful, interested students, and provided the caring needed by students to increase their identification with engineering, science, and computer science. The increases in these beliefs also led to the high "effort" that youth dedicated to Studio STEM, and the claims that youth would "choose" to take a course in these subject areas even if they were not required to do so.