With societies experiencing growing cultural diversity through international mobility of people, there are concerns about negative attitudes towards immigrants. These concerns have prompted the importance of multicultural learning at schools, which has resulted in a plethora of research on the relationship between students' multicultural learning and attitudes towards immigrants. Yet, prior research has concentrated on student- and classroom-level characteristics in this relationship; therefore, the contextual influences of school- and country-level factors remain unclear. The present study aimed to uncover the influence of teachers' multicultural beliefs and countries' immigrant integration policies on the relationship between students' multicultural learning and attitudes towards immigrants. To this end, student- and school-level data from 206,291 students in 11,285 schools that participated in the Programme for International Student Assessment (PISA) 2018 was combined with country-level data from 38 countries represented in the Migrant Integration Policy Index (MIPEX) 2018. Multilevel regression analyses revealed that students' multicultural learning is positively associated with their attitudes towards immigrants. Furthermore, a significant interaction between students' multicultural learning and teachers' multicultural beliefs was found, suggesting that egalitarian values of teachers at school enhance the positive effect of multicultural learning on students' attitudes. However, countries' immigrant integration policies did not play a moderating role. These findings underscore the significance of not only students' multicultural learning but also teachers' multicultural beliefs in shaping students' attitudes towards immigrants, contributing to strategies for promoting inclusion in diverse educational settings.