When rebels also employ terrorism, civil wars can become more intractable. Since the 1980s, jihadism, a form of violent transnational activism, has mobilized civil war rebels, outside entrepreneurs, foreign fighters, and organizers of transnational as well as domestic terrorism. These activities are integral to the jihadist trend, representing overlapping and conjoined strands of the same ideological current, which in turn reflects internal division and dissatisfaction within the Arab world and within Islam. Jihadism, however, is neither unitary nor monolithic. It contains competing power centers and divergent ideological orthodoxies. Different jihadist actors emphasize different priorities and strategies. They disagree, for example, on whether the “near” or the “far” enemy should take precedence. The relationship between jihadist terrorism and civil war is far from uniform or constant. This essay traces the trajectory of this evolution, beginning in the 1980s in the context of the Soviet invasion of Afghanistan.