The large-scale internal migration from countryside to city over the past 30 years has transformed China's demographic, social, economic, and educational landscapes. There were approximately 35.81 million children below age 18 living with their migrant parents in urban cities without local registration of permanent residence ("Hukou"). Migrant children and their families face many challenges in migrant destinations, such as discriminations, economic insecurity, educational inequality, lack of access to health care, and social exclusion. Migrant children face special difficulties in adapting to new environments, securing quality education, enjoying adequate parental attention, and living in adequate housing. Those children are often denied admission to urban public schools and have to attend schools created mainly for migrant children with insufficient educational resources and poor teacher quality. The migrant children who have the opportunity to attend public schools suffer discrimination from teachers and local urban-resident classmates. Family disadvantages and institutional barriers potentially undermine academic achievement and psychological wellbeing of migrant children. Developing policy and practice to address the critical needs of these children are not only important in itself because of the large number of migrant children involved, but also essential for the future of urban China.