<p>Food insecurity remains a crucial issue across the globe, including in developed countries. In this study, we examined the relationship between food insecurity and student math achievement globally. We used novel, student-level data from about half a million students in 65 countries that participated in the Program for International Student Assessment (PISA) 2022. We applied three-level hierarchical linear regression models to analyze the data. Without an exception across countries, we found a consistent relationship between food insecurity and student achievement which remains robust after accounting for student and school demographics and socioeconomic status. Students who experience the most severe food insecurity fall behind their food-secure counterparts by approximately two academic years. This substantial achievement gap necessitates profound policy response on a global scale.</p>