In the era of globalization along with the growing concerns about human rights, the cultural diversity of people in Thailand has obtained increasing attention. With the influx of migrant workers, schools in Thailand nowadays serve even more diverse population—the majority Thai, the ethnic minorities, and children of migrant workers. Using qualitative research methods, this research examines Thailand’s multicultural education policy. The result of the research shows that certain education policies meet the basic principle of multicultural education. For example, schools are allowed to provide Muslim studies for Muslim students. The government provides substantial amount of financial and technical support for Islamic religious institutions. Schools have the liberty to decide school holidays and school uniforms that suit with students’ cultures. Children of migrant workers can get access to public schools. However, schools’ practices on these policies vary, depending on areas, group politics, and ratio of minority students in schools. In the area where the politics of cultural groups are strong, schools have more culturally relevant practices. School administrators’ perceptions on cultural diversity also play an important role in school practices for culturally diverse students.