This paper studies the relationship between ethnic school composition and classroom disruption in secondary education in the context of migration policies. We measured classroom disruption using students' reports from 3533 schools in 20 countries provided by cross-national PISA (Programme for International Student Assessment) 2009 data. We employ the migrant share and the ethnic diversity net of the native share as indicators of the ethnic composition of a school. The MIPEX (Immigrant Integration Policy indEX) is used as an indicator of migration policies. Our results show a positive association between ethnic school diversity net of the migrant share and classroom disruption. Furthermore, we show a negative interaction term of the migration policy and ethnic diversity. Consequently, our results indicate that students in countries with a more inclusive migration policy are at least less harmed by influence of ethnic school diversity regarding classroom disruption. Findings partly support the "contact hypothesis" and reject the "threat hypothesis" in an educational context.