Social movements are associated with large societal changes, but evidence of their causal effects is limited. We study the effect of the MeToo movement on reporting sex crimes to the police. We construct a new dataset of crimes reported in 31 OECD countries and employ a triple-difference strategy between crime types, across countries, and over time. The movement increased the reporting of sex crimes by 10%. Using rich US data, we find that in contrast to a common criticism of the movement, the effect is similar across socioeconomic groups, and that the movement also increased arrests for sexual assault. The increased reporting reflects a higher propensity to report sex crimes and not an increase in crime incidence. The mechanism most consistent with our findings is that victims perceive sexual misconduct to be a more serious problem following the movement. Our results demonstrate that social movements can rapidly and persistently affect high-stakes decisions.