This chapter examines migrant children’s education in Japan from the perspective of bottom-up multicultural education. Drawing from Modood’s (Multiculturalism: A civic idea, Polity Press, 2008) discussion of multiculturalism as a civic idea, this study examines initiatives led by local actors and the government’s approach to educational diversity. This chapter argues that while the government has been slow to introduce culturally responsive education policies, they are building inclusive education from the bottom-up through progressive initiatives at the local level. It scrutinizes how the curricula, school ethos, and educational policies are developed in response to the cultural and linguistic diversity of the student population, and points out that these initiatives have been built on the accumulation of rights-based educational initiatives for other minority groups. It also draws on the tension between neoliberal educational policies and social-justice oriented education using multicultural high schools that have developed inclusive and empowering school environments based on social justice and human rights.