This special issue of Small Wars and Insurgencies examines the phenomenon of jihadist insurgencies. It explores the strategic, political, and ideological significance of some of these movements operating in the Middle East and North and West Africa. These movements have become an increasingly important part of modern irregular warfare though they are by no means new on the international political landscape. They are termed ‘jihadist’ insurgent movements though not all are attached solely to waging guerrilla warfare. Some have evolved quite a larger military repertoire encompassing terrorism, suicide bombing, and assassination; in some parts of the Middle East and Libya, the huge supply of weaponry has led to conflict escalating almost to the level of a conventional small war, involving artillery, air strikes, trench warfare, and bitter urban battles.