This study examines teaching and learning economics and entrepreneurship through a student-run Montessori middle school store. By designing and managing a school store, students created a "community of practice" to learn economics concepts in their daily environment. Questions guiding this study were: (a) How do students' social-interactions in a Montessori middle school student-operated business demonstrate economics content knowledge? (b) How do students' social-interactions in a Montessori middle school student-operated business demonstrate economics skills? (c) How do students' business roles in the store develop their understanding of economics principles? Findings indicate that: (1) student activities in the school store promoted learning through social interaction; (2) the type and number of business roles a student assumed created opportunities for economic learning; (3) student entrepreneurs expressed specific knowledge of economics concepts, and, (4) students' decision-making and ownership affected behavior. Additionally, features of Kohlberg's (1985) concept of Just Community supported the learning environment. This study can provide social studies teachers and teacher-educators with a model for learning economics (or social studies) concepts through a curricular-based student-run enterprise. (Contains 5 tables.)