Nailul Mona, Irwansyah , Contagion Mechanism on Social Network (Bullying on Teenage Peer Group), The Social Sciences, Volume 11,Issue 19, 2016, Pages 4599-4602, ISSN 1818-5800, sscience.2016.4599.4602, (https://makhillpublications.co/view-article.php?doi=sscience.2016.4599.4602) Abstract: Contagion mechanism makes certain behavior spread and imitated on social network. This mechanism occurs in two way, by cohesion and structural equivalence. This mechanism also can occur in the bullying behavior of teenage student. Study conducted on peer group network in the boarding school, consist of six generation high school student. This study using mixed method approach and snowball sampling technique with social network analysis method. The results shows that contagion occurs not only by cohesion and structural equivalence but also by reversed structural equivalence. And contagion by cohesion are dominant in this bullying network. Keywords: Social contagion;contagion mechanism;bullying;social network;communication;mixed method