There is a long-standing debate over the impact of coups on democratization. Some argue that coups can help promote transitions to democratic rule. Yet, others contend that coups often spur increased repression and autocratization, undermining hopes of democratic reform. We argue that both democratic and autocratic changes are more likely after a coup and that popular mobilization plays a crucial role in shaping the post-coup trajectory. Democratization is more likely when coups occur in the presence of significant popular mobilization. A coup reveals cracks within a regime, and the combination of pressure from within and threat from below during popular mobilizations fosters greater incentives to promise democratic reform. In the absence of popular mobilization, autocratic rule is more likely, especially when a coup is successful. We test our argument on the combined effect of popular mobilization and coups on changes in democracy in a global dataset, considering the specific dates of events and institutional changes, the outcomes of coups, and using decay functions to capture persistent effects. The analysis provides strong support for our argument, with the key findings robust across a number of alternative tests. Our analysis underscores the value of examining variation in the context of coups to understand their likely political consequences.