The population with migrant backgrounds continues to grow in Korea. Despite these rapid demographic changes, research on the current status of and demand for social security among this population remains scarce. Focusing on public assistance systems for migrants, this study consists of three main components: a theoretical review of migrants' social rights, an international comparison of 12 countries across four welfare regimes, and policy case studies of Japan and the United Kingdom. Based on the analytical results, the study proposes a policy direction that gradually grants public assistance rights to settled migrants.