The purpose of this paper is to use criminological theories to explain the root causes of terrorism and why it prevails. Three criminological theories will be implemented to describe this behavior: rational choice theory, social learning theory, and anomie/strain theory. Using these theoretical concepts, the researcher will first contend that some terrorists are rational actors who learn criminal behavior from social and non-social sources. The researcher will then illustrate that institutional decay and lack of opportunity contributes to political extremism. This paper will conclude with theoretical limitations and policy recommendations.