We identify start days of 156 episodes of social unrest from textual analysis of media reports and show a systematic negative impact of social unrest on stock market performance. Social unrest on average leads to a 1.4 percentage point drop in cumulative abnormal returns in 2 weeks, more for events that last longer and that happen in emerging markets. Stronger institutions, particularly better governance and more democratic systems, are associated with a smaller adverse impact of social unrest on stock market returns. We argue this reflects the ability of better institutions to provide a more reliable way to reconcile conflicting views and dampen uncertainty after unrest.