This study used a nationally representative dataset of 21,260 kindergartners, Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (National Center for Education Statistics, 2001a), and a conceptual framework of theories of cultural and social capital (Bourdieu, 1986) embedded in an ecological framework (Bronfenbrenner, 2005) to identify unobserved socio-cultural classes in families of kindergartners and investigate these families' involvement at school. The study focused on the differences between families of children with and without disabilities.;Latent Class analysis (LCA) was used for determining unobserved group membership in parents. First analysis revealed four socio-cultural classes: a low class of predominantly White, English-speaking, low education, and low socio-economic status (SES) parents; a middle class of predominantly White, educated, English-speaking, and high SES parents; a high class of educated, high SES parents, regardless of race or home language; and an "atypical" class of moderately educated, non-White, and non-English-speaking parents, regardless of their SES. Presence of disability did not influence socio-cultural class membership, but within each class, families of children with and without disabilities differed on a number of characteristics.;The second analysis identified three groups of parents based on school involvement: low, medium, and high involved. Group membership was predicted by four family factors: socio-cultural class, family structure, family-school ethnic match, and family's perception of school's involvement practices. Two-parent families, of higher socio-cultural class, with higher ethnic match, and with more positive perceptions of school practices belonged to the higher involvement group. School and teacher factors, including resources, views, and practices, had a weaker influence on parent involvement. School practices for parent-school involvement had only an indirect effect on parent involvement, through parent's perception of school practices. Disability status did not predict parent involvement group membership; however, within each group, the parents of children with disabilities were generally more involved, especially in the low-involvement group. The parents in the atypical and the low socio-cultural classes differed on a number of characteristics, including prevalence of disability and school involvement, differences that a classical SES categorization would more likely obscure. The study has important implications for informing better school-family connections.