In both scholarly and policy circles around the world, much attention has been paid to multicultual policy as it purports to manage diversity in face of increased international migration. Despite the cross-national spread of multicultural policies, little effort has been made for systematic policy evaluations. As an attempt to fill this research void, this study focuses on the effect of multicultural anti-discrimination policy, especially in relation to its effect on truancy reduction for immigrant children. Using a sample of approximately 224 thousand children (aged 15 years old) selected from more than nine thousand schools across 29 OECD member states, a three-level logit analysis based on hierarchical generalized linear modeling has been conducted. The main findings clearly suggest that the degree of institutionalization of multicultural anti-discrimination policy at the country level is strongly associated with truancy reduction for immigrant children. This provides a piece of illustrative evidence that multicultural policy, if implemented successfully, could work as intended toward social integration in a diverse society.