This study examines fiscal sustainability in Latin American countries from a unique time–frequency perspective, focusing on Brazil, Chile, Colombia, Peru, and Mexico from 1997 to 2022. Using wavelet coherence analysis, it uncovers dynamic relationships between government revenue and expenditure over different time horizons, revealing varying causality patterns across countries and periods. The findings underscore the importance of balanced fiscal planning and resource allocation to ensure fiscal sustainability and support economic growth. This research contributes to a deeper understanding of Latin America’s economic landscape and provides valuable insights for policymakers, economists, and stakeholders concerned with the region’s economic stability and development. © 2024 by the authors.