Day to day governance of civilians is not solely the purview of states. Rulemaking, rule-enforcing, and goods and services provision are central components of governance, yet in many instances it is non-state aReykoctors who assume these functions. We advance the study of governance by rebel groups engaged in armed confrontation against state governments. We identify five key areas of research where the field of rebel governance is best poised to go: the study of multi-level governance, rebel use of self-constraining or hand-tying behaviors, synergy between institutional form and domestic legitimacy, the nuanced role of territorial control in governance, and short- and longer-term impacts of rebel governance on post-conflict outcomes. In each area, we draw attention to the lessons already learned, interrogate key assumptions in existing work, raise arguments that remain under- or uninvestigated, and focus on the next frontier in the exploration of rebel governance. Learning more about the ways that rebel groups govern informs our understanding of armed conflict and its resolution, as well as provides broader lessons about the study of governance.