This paper studies whether mandatory ESG disclosure reduces, reveals, or increases greenwashing. If such mandates discipline firms, one would expect fewer misleading ESG claims. Instead, analyzing staggered ESG disclosure mandates across countries, we find that the number of detected ESG misrepresentation incidents rises after mandates take effect. This increase is concentrated in settings where detection is more feasible, such as countries with strong media freedom and firms with high public visibility. Incidents also elicit stronger negative reactions in stock prices after the mandate. These patterns are more consistent with improved detection by external monitors than with increased misleading behavior, and suggest that disclosure mandates enhance the visibility and financial relevance of ESG performance.