This research tested a mediation model, examining whether individual differences in mothers' school readiness beliefs influenced home literacy practices and children's later academic achievement among African American (n = 114) and primarily Mexican origin Latina mothers (n = 164) and their children. Mothers of children ages 3-4 years reported school readiness beliefs and home literacy practices. Later (ages 6-7 years), reading and math achievement scores were measured using the Woodcock-Johnson Revised (WJR) or the Batería Woodcock-Muñoz, as appropriate, depending upon the child's primary language. "Research Findings:" Results showed that African American and Latina mothers differed in their beliefs about school readiness skills, with African American mothers more likely to emphasize general pre-academic knowledge and Latina mothers more likely to emphasize social-focused readiness skills. Academic-focused readiness beliefs predicted mothers' engagement in home literacy practices, social-focused readiness beliefs predicted math achievement, and home literacy practices mediated the association between academic-focused readiness beliefs and math achievement. "Policy or Practice:" Findings suggest that interventions to enhance school readiness should consider ethnic minority parents' expectations and at-home practices, particularly during children's early childhood.