Child Welfare Systems and Migrant Children examines where, why and to what extent immigrant children are represented in the child welfare system in different countries. These countries include Australia/New Zealand, Belgium/the Netherlands, England, Estonia, Canada, Finland, Italy, Germany, Spain, Norway, and the United States–all of them having different child welfare philosophies and systems as well as histories and practices in immigration. By comparing policies and practices in child welfare systems (and welfare states), especially in terms of how they conceptualize and deal with immigrant children and their families, we address an immensely important and pressing issue in modern societies. Immigrants in the child welfare system are a critical issue and they seem to face serious challenges that are evident across countries. These are challenges related to lack of language proficiency, lack of knowledge about cultural and social aspects and about the public systems of the destination country. Perhaps most relevantly, the challenges may include collisions of ideas and beliefs about how to raise children, about children’s place in the family and society, and about children’s rights.