Since 2000 the world has witnessed the rise of Islamic radicalism in Southeast Asia. This paper would like to see Islamic radicalism as a social movement by focusing on the process of collective identity formation. The author argues that collective action is not a given reality but is the outcome of the construction and consolidation of internal identity. That is why without understanding the construction of internal coherence; it is difficult to understand the logic of actions undertaken by the activists. This paper draws analysis from five radical islam organizations: Forum Komunikasi Ahlus Sunnah wal Jamaah (FKASWJ) and its military wing Laskar Jihad (LJ), Front Pembela Islam (FPI), Majelis Mujahidin Indonesia (MMI), Hizbut Tahrir Indonesia (HTI) and Jamaah Islamiyah (JI).