This chapter examines the significance and background of ‘well-being’ and its challenges as set out in the Fourth Basic Plan for the Promotion of Education in Japan. As a premise for the analysis, we will refer to the ‘educational welfare theory’ that emerged in Japan in the late 1960s and examine its continuity and discontinuity with the contemporary discourse on children’s well-being. While the issues of educational welfare have in the past been discussed in terms of long-absent children, poor and discriminated children, and children with disabilities, well-being was introduced in 2022 as a central concept in the Fourth Basic Plan for the Promotion of Education, resulting in child welfare and well-being attracting renewed attention. In Japan, the term ‘educational welfare’ began to be used as an interdisciplinary technical term after 1965. Toshio Ogawa defined educational welfare as “a concept that aims to systematize the guarantee of learning and educational rights for children, adolescents, and adults, which have been left substantively very vague and consequently neglected and deprived in today’s social welfare, especially child welfare services” (Ogawa & Takahashi, 2001). The research method applied was to examine administrative and other documents that show the process of formulating the Fourth Basic Plan for the Promotion of Education.