The events of the Arab Spring of 2011 have made clear the importance and potential efficacy of nonviolent resistance, as well as the field’s inability to explain the onset and outcome of major nonviolent uprisings. Until recently, conflict scholars have largely ignored nonviolent resistance. This issue features new theoretical and empirical explorations of the causes and consequences of nonviolent resistance, stressing the role that unarmed, organized civilians can play in shaping the course of conflicts. Contributors demonstrate the importance of treating nonviolent and violent strategies, as well as conventional politics strategies, as alternative choices for engaging the state, show how gender ideology can influence which opposition groups use nonviolent resistance, and suggest that the causes of civil war and nonviolent resistance often differ. Other pieces highlight the role of public attitudes regarding whether nonviolent resistance and violence are employed, how experience with activism and repression by the state can shape activists’ perceptions of justice, and how the perceptions of resistance leaders can influence strategic choices. Moreover, several articles examine the key role that security force defections can play in the success of nonviolent resistance, how micro-level nonviolent tactics can improve security in civil war, and how nonviolent campaigns can influence the stability of autocratic states. These contributions suggest that rigorous empirical study of civilian-based contentious politics (rather than only violent contention by armed non-state actors) must be incorporated into the conflict literature. Improved theory and data on the subject will help researchers and policymakers to shape strategies to support these movements when appropriate, and to manage changes in the international system that result from the success of nonviolent uprisings.