The impact of social class backgrounds on young children's educational experiences has attracted increasing attention in early childhood research. However, few longitudinal studies related to social class and parental involvement in young children's education are available, especially in East Asian contexts. In this longitudinal qualitative study, I examined middle-class and working-class mothers' beliefs related to education and processes through which they support their children's education from preschool to second grade in Japan. Sixteen Japanese mothers were recruited from preschools and four in-depth interviews along with home visits were conducted over 3 years. Findings of this study demonstrated that both middle-class and working-class mothers hoped that their children would do well academically, but their beliefs related to parenting roles and development of the children's learning interest differed. Such distinctive maternal beliefs affected their ways of supporting their children's education in everyday contexts.