This research amis to obtain information on: (1) Students’ interaction in social groups, (2) roles of social groups in shaping students’ religious behaviour at SMP (Junior High School) MBS Sleman Yogyakarta, (3) students’ religious behaviour resulted from the roles of social groups in shaping their behaviour. This research is a descriptive qualitative study conducted at SMP Muhammadiyah Boarding School Sleman Yogyakarta. The data Wet collected using observation, interview, and documentation. The dinding show that: (1) The interaction of Nasheed group is divided into contact and involvement stages. The interaction among internal and external members have been included in the contact (introduction) stage, while the involvement stage is only found in the interaction of internal Nasheed group. (2)The roles among Nasheed members, in addition to facilitate them in improving the spirituality through organized religious agendas of the school, also through singing scadule is used to do Activities such a discussion about religion, to introspection about social and religious behaviour of each members, as well as a forum to motivate Beach other in religious. (3)The Nasheed group gives positive impacts to its members in some dimensional namely faith, woeship, and practice. (4) The Nasheed group give positive impact in religious for its members are found in their mental and mind development, emotion development, moral development as well as attitude interest development, social considerations, and worship. In addition, the Nasheed group give positive impact on the cognitive development of its members trough the stages of scheme, organization, and adaptation.