Using propositions within critical race theory, this study examined differences between parent and teacher engagement in ethnic-racial socialization and links between parent--teacher congruence in ethnic-racial socialization and children's social and emotional development across racial and ethnic groups. The participants were 59 parents or guardians and their preschool-aged children from diverse ethnic-racial backgrounds and 12 Head Start teachers. Parents used ethnic-racial socialization more than teachers; parents and teachers used egalitarian messages most frequently. Bayesian analyses revealed significant ethnic-racial group differences in parents' use of egalitarian, preparation for bias, and cultural socialization messages. Gender and race had significant impacts on teacher-reported protective factors. Mismatch in parent-teacher levels of egalitarian and cultural socialization were evident predictors of lower social-emotional functioning in children. Findings highlight the importance of ethnic-racial socialization in Head Start children's early social development and may be useful in informing early childhood practices relating to cultural continuity.