Under what conditions do successful revolutions come to be overthrown by counterrevolutions? This paper develops and tests a theory to explain the emergence and success of counterrevolution, which I define as an effort in the aftermath of revolution to restore a version of the pre-revolutionary regime. Contrary to existing explanations, which focus exclusively on the actions of old regime elites, I argue that counterrevolutions often have a popular base. Specifically, I propose that counterrevolutions are made possible by the support of a minority player in the revolutionary coalition itself. In the aftermath of revolution, as new governing arrangements are negotiated and nascent institutions erected, some coalition members may come to believe that their interests were, in fact, better served under the old regime. They turn against their former revolutionary allies, returning to the streets to protest their perceived marginalization. They then form an alliance with remnants of the old regime and foment a counterrevolution through a combination of elite intervention (often a coup) and popular mobilization. The research is anchored by the case of Egypt, which experienced a revolution in 2011 and, after a tentative two-year experiment with democracy, succumbed to a counterrevolution that restored an autocratic military ruler to power. To analyze the sub-national events that brought about this counterrevolution I draw on two methods of analysis: process tracing and event analysis. Using process tracing in the case of Egypt, I identify the key decisions, events, and conjunctures that prompted secularists to defect from Egypt’s revolutionary coalition and embrace a counterrevolutionary alternative. I draw on interviews with members of the primary political and activist groups that participated in the revolution and the subsequent transition period, including members of the Muslim Brotherhood, the secular opposition, and the old regime. I combine process tracing with quantitative event analysis, which entails the systematic tracking of different forms of contentious collective action over time. Using a dataset of contentious events collected from the year preceding the counterrevolution, I analyze the patterns of counterrevolutionary mobilization that created the conditions for military intervention on July 3, 2013. Finally, to demonstrate the generalizability of the theory I compare Egypt’s experience to post-revolutionary trajectories in four shadow cases: two Middle Eastern revolutions that bred durable regimes (Iran 1979 and Tunisia 2011), and two non-Middle Eastern cases that succumbed to counterrevolution (Guatemala 1944 and Thailand 1973).