This article is an attempt to answer a number of questions asked in the literature on radicalization and extremism: What motivates foreign terrorist fighters (FTFs) from Turkey to join the Islamic State of Iraq and Syria (ISIS)? In what kind of environment does violent extremism become the choice for Turkish nationals to join ISIS in Syria and Iraq? How can Turkish nationals who join ISIS be profiled in terms of their socio-economic and cultural traits and how do these traits compare people from other nations who join and fight in terrorist organizations? Though their numbers remained minimal compared to the overall population, how can we explain the case of Turkish FTFs, when a peaceful and tolerant Anatolian/Sufi Islam' has reigned in the country and Muslims are well integrated in the social, economic, and political life of the country under the 13-year long rule of Islamic-oriented Justice and Development Party (AK Party)? What do these answers to these questions mean for Turkish Islam and possible de-radicalization programs? These questions will be addressed by semi-structured interviews conducted both with Turkish FTFs who have joined ISIS and with family members of some of those who have returned from fighting with ISIS.