This chapter examines how government announcements influenced mask-wearing compliance in Latin America during the COVID-19 pandemic. Drawing on data from the University of Maryland Global COVID-19 Trends and Impact Survey and employing regression discontinuity design alongside fuzzy-set qualitative comparative analysis, the research analyzes 75 policy announcements to assess short-term behavioral changes. Findings reveal that encouraging mask-wearing is more effective than discouraging it, with success hinging on two key factors. First, the study identifies a “ceiling effect,” where high pre-announcement mask usage limits the impact of further encouragement. Second, counterintuitively, mask-wearing announcements are more effective during stable or declining infection trends than during rising ones. Regarding state capacity, the research challenges the assumption that strong capacity guarantees compliance, showing that behavioral change often arises from self-protective motivations rather than government effectiveness. These findings suggest that effective public health messaging requires strategic timing and a nuanced understanding of societal behavior.