This meta-analytic review examines the relationships between students' sense of school belonging and students' motivational, social-emotional, behavioural, and academic functioning in secondary education. Moreover, it examines to what extent these relationships differ between different student groups (grade level, SES), measurement instruments, and region. The meta-analysis included 82 correlational studies, published in peer-reviewed journals between 2000 and 2018. Results revealed, on average, a small positive correlation with academic achievement, and small to moderate positive correlations with motivational outcomes such as mastery goal orientations; with social-emotional outcomes such as self-concept and self-efficacy; and with behavioural outcomes such as behavioural, cognitive, and agentic engagement. A small negative correlation is observed with absence and dropout rates. Similar results are found across different student groups (grade level, SES). Although the results vary to some extent across measurement instruments and region, generally, the results reveal that school belonging plays an important role in students' school life.