Prevention strategies for terrorist attacks commonly incorporate all aspects of radicalization, aiming to deter terrorist attacks by countering radical beliefs. In this article, however, we argue that the cognitive aspect of radicalization is not necessarily interconnected with its behavioral aspect and thus cannot reliably predict terrorist violence. It is therefore necessary to distinguish between them in prevention efforts, and to differentiate them from cognitive and behavioral extremism. We specifically discuss the Attitudes-Behaviors Corrective model, a recent model conceptualizing the distinction between cognitive and behavioral extremism. This model additionally theorizes what might be driving behavioral extremism, independent from cognitive extremism. We explore how prevention efforts diminish in accuracy when conflating extremist beliefs and actions and propose that utilizing behavioral warning signals might provide an encouraging solution. Empirical studies indicate that behavioral indicators might be able to detect those who are planning violent terrorist acts and show promising capacity for their use in threat assessment. We review two threat assessment tools using behavioral warning signs, the TRAP-18 and LATERAN-IT, and conclude that these tools seem capable of identifying those who are planning terrorist violence. More research is needed to further validate and eventually implement these tools in the prevention of terrorist attacks.