This study focuses on the determinants of radicalization among university students in Turkey. It investigates how social and political context and the “radical milieus” affect the ethnic, ideological and religious radicalization among them. Radical milieus are defined as “the segment of a population which sympathizes with extremists/ terrorists and supports them morally and logistically by Peter Waldman. The study is based on field research conducted in 11 cities and 14 universities in Turkey in 2007 and 2008. The sample covers all geographical regions and universities located in these regions. The research team conducted more than 160 in-depth interviews with the students, university administrations, faculty members, student residence administrators and the members of civil society organization. Our analysis on social networks and organizational ties offer several contributions to scholarship on social mobilization, radicalization and identity literature. The findings suggest that the competition between radical groups and the diversification of their ethnic, religious and ideological has significantly increased in Turkey. Radicalized students refrain from violent political action, but sympathizes with the ideas that support violence against the state. The research also finds significant differences in having sympathy with radical ideas among students with ethnic, religious and ideological radicalism.