Jihadist Foreign Fighters and ‘Lone Wolf’ Terrorism

Publication Type:

Book Chapter


Sam Mullins


Combating Transnational Terrorism, Procon, Sofia, p.115-130 (2016)


By April 2015, it was estimated that more than 25,000 ‘foreign fighters’ from perhaps as many as 100 different countries around the world had flocked to Syria and Iraq. Most are believed to have joined the so-called ‘Islamic State’ (IS) or al-Qaeda’s (AQ) official representative in the region, Jabhat al-Nusra (JN). Not only does this contribute to continued instability in the Middle East, but it also raises the risk of terrorist attacks committed by foreign fighters if and when they return home. Indeed, this has already begun to happen with successful attacks in Egypt in September 2013, Belgium in May 2014 and Paris in November 2015. This is not to mention many historical cases as well as continued terrorism threats emanating from Afghanistan, Somalia and Yemen among other places. At the same time, there are increasing reports of ‘lone wolf’/ lone-actor terrorism where people inspired by IS or AQ, who have not received terrorist training overseas, carry out attacks on their behalf. As a result, we have seen unprecedented levels of mobilization to violent jihad and an increased threat of terrorism worldwide. This chapter begins by clarifying what is meant by ‘foreign fighters’ and ‘lone wolf’ terrorism and then describes how these related challenges to global security have developed and escalated over time. It then examines who is getting involved, how and why they are becoming radicalized and what they are doing in pursuit of violent jihad. The chapter concludes with a discussion of key concerns for counter-terrorism (CT).