Research on the relationship between civil conflict and repression has led to one conclusion—the law-like finding that states respond to internal challengers with repression—and one puzzle with competing hypotheses—whether state repression escalates civil conflict or not. Studies of repression’s effect on conflict dynamics have been limited to case studies and subnational designs, which limits the external validity of the arguments. Studies of conflict’s effect on repression have treated conflict as a control variable without taking into account the inherent endogeneity between internal conflict and state repression. This article contributes by providing a general, cross-national study of repression’s effect on conflict, and vice versa, for external validity. Results of simultaneous equation models demonstrate that both directions of the relationship between state repression and conflict are positive and significant—suggesting a cyclical relationship—while single equation models with a lag structure establish that the effect of repression on conflict is greater than the reverse.