When do autocrats employ propaganda to threaten citizens with repression? Do threats of repression condition citizen behavior? This article develops a theory of propaganda-based threats in autocracies that builds on insights from experimental psychology. It argues that even credible threats of repression are costly, and so are reserved for moments when collective action is most likely. Since threats of repression are employed sparingly, the authors also expect them to be effective. The theory is tested using data from China, the world's most populous autocracy. The study analyzes all 164,707 articles published between 2009 and 2016 in the Workers' Daily, a state-run newspaper that focuses on domestic issues and targets a non-elite audience. It finds that the Chinese government employs propaganda-based threats of repression primarily around the anniversaries of ethnic separatist movements in Tibet and Xinjiang regions. Using an instrumental variables strategy, the study shows that these threats decrease protest rates by a substantively meaningful margin.