Militias of various kinds, such as pro-government militias, paramilitaries, vigilantes, death squads, and civil defense forces, are common features of many civil conflicts around the world. They are also prevalent in “ethnic conflicts.” Ethnic mobilization into militias, where recruitment into such armed groups takes place across ethnic divides, constitutes an important facet of many ethnic conflicts. From Serbian pro-state militia forces during the breakup of Yugoslavia, to the “Arab” Janjaweed fighters in Sudan, to Pashtun Achekvai militias in Afghanistan, and to Kurdish Village Guards in Turkey, pro-government militias mobilized and recruited along ethnic lines are common. This chapter provides an overview of some of the literature on militias in ethnic conflict. It highlights and draws distinctions between specific conceptualizations and categories of militia forces, such as “ethnic militias” and “ethnic pro-government militias” as well as subcategories of the latter, such as “ethnic defectors” and “rival militias.” It highlights some common approaches to theorizing the mobilization of ethnic militias. It then covers some empirical research into their impact on conflict dynamics.