Approved for public release; distribution is unlimited / Reissued 5 May 2017 to correct misspelled Second Reader’s name on title page. / The number of disconnected youth, those ages 16 to 24 who are not in school and are not employed, has reached significant levels in the United States and Western Europe. This trend is coupled with the fact that more and more foreign fighters are joining Islamic State in Iraq and Syria (ISIS) in Iraq and Syria. In particular, Western youth have been the target of radicalization by ISIS and other terrorist groups, and the appeal and lure of such groups seem unlikely to subside. A similar trend is also evident among youth in Muslim countries where the number of foreign fighters to terrorist groups seems unlikely to decrease. According to recent estimates, over 28,000 foreign fighters have joined ISIS in Syria and Iraq since 2011. The fact that so many youth have been radicalized to join terrorist groups is a cause for concern that requires closer scrutiny, understanding, and action by Western and other governments. The explanations and motivations as to why youth join terrorist groups abound; these include lack of education, poverty, religion discrimination, family background, and political and economic marginalization, among others. This research seeks to answer the question, are the youth in the United States, who are disconnected, more likely to become radicalized to terrorism? To answer this, various theoretical frameworks were researched and examined, such as relative deprivation, social movement theory, and psychological perspectives, to shed light on understanding this issue. / Director, Personnel Support Services and Benefits, Transportation Security Administration