Students' school belonging is critical to overall functioning. Most past studies of school belonging's antecedents focused on individual-level and proximal environmental factors, neglecting broader socioecological factors such as income inequality. Hence, this study examined whether income inequality is associated with students' school belonging. We further examined whether having high socioeconomic status could buffer the harmful consequences of income inequality on school belonging. We drew on 822,230 students' survey responses from 65 countries/regions using 3 waves of data (2000; 2003; and 2012) from the Program for International Student Assessment (PISA). Multilevel and cross-temporal analyses were used. Results showed that country-level income inequality in the past year was associated with lower school belonging, controlling for other variables at the country, school, and student-levels. School and family socioeconomic status moderated the effects of inequality. More specifically, for students in more affluent schools and more advantaged families, the association between inequality and belonging was weaker. This study demonstrates the importance of income inequality and the buffering role played by socioeconomic status in school belonging. Theoretical and practical implications are discussed.