When identifying parental socialization processes influencing children's reading achievement, building self-regulation is a potential underlying mechanism. Yet socialization (i.e., warmth, stress) of self-regulation may vary based on the sociocultural context of ethnic minority families. Using the ECLS-K: 2011 (N = 17,020; M[subscript Age] = 73.43 mos, SD = 4.48 mos), we explored: (RQ1) Do kindergarten approaches to learning (ATL), a composite of self-regulation behaviours in the classroom context, mediate the association between parental warmth and stress and first grade reading? and (RQ2) Is mediation moderated by race/ethnicity (White, Black, Hispanic, Asian)? ATL mediated the association between parental warmth and stress and reading, such that parental warmth contributed positively to reading through higher ATL, and parental stress contributed negatively to reading through lower ATL. However, the lack of moderation suggests that the adaptiveness of parental warmth and maladaptiveness of parental stress for children's reading through ATL may be similar across race/ethnicity. Findings inform intervention and practice targeting children's school readiness.