This qualitative case study (N = 24) analyzed in what ways school-based interpersonal relationships may have helped to set the foundation for young adolescents' belonging within 1 large, diverse urban sixth through eighth grade middle school. Eighteen students (11-14 years old), 5 teachers, and 1 administrator were individually interviewed in the spring of 2011. Findings revealed responsive teacher-student and student-student relationships may have helped to lay the groundwork for the promotion of young adolescents' sense of school belonging. Responsive teacher-student relationships where teachers fostered caring connections and responded to student needs may have served as a way to help promote students' sense of belonging. Responsive student-student relationships where young adolescents felt known and accepted by peers and received academic and emotional peer support may also have served as a way to help promote school belonging. Fostering responsive, school-based interpersonal relationships with students that are both academic and social in nature emerged as the major theme in setting the foundation for young adolescents' belonging in middle school. Implications for educators are discussed.