Radicalization is a process by which individuals are introduced to an ideological belief system that encourages political, religious, or social change through the use of violence. Here we formulate an obsessive‐compulsive disorder (OCD) model of radicalization that links obsessive passion (OP; one of the best predictors of radical intentions) to a larger body of clinical research. The model's central tenet is that individual differences in OCD symptom severity could shape radical intentions via their influence on OP. Across four ideological samples in the United States (Environmental activists, Republicans, Democrats, and Muslims, Ntotal = 1114), we found direct effects between OCD symptom severity and radical intentions, as well as indirect effects of OCD on radical intentions via OP. Even after controlling for potential individual difference and clinical confounds (e.g., adverse childhood experiences, loss of significance, and substance abuse), these relationships remained robust, implying that OCD plays a significant role in the formation of violent ideological intentions and opening new avenues for the treatment and prevention of violent extremism. We discuss the implications of conceptualizing radicalization as an OCD‐like disorder with compulsive violent tendencies and ideology‐related concerns.