Background: Most research on the relation between parenting behaviors and child outcomes has not focused on cross-ethnic variation in these relations. Objective: This study examined if ethnicity moderates associations between parenting, child agency/persistence, and child academic achievement and social competence. Design: Participants included 608 parents and their 5-year-old children (96 African American, 117 Hispanic, and 395 European American). Parenting was assessed with the Parent Behavior Inventory (support/engagement, hostility/coercion) and a semi-structured interaction paradigm, the NICHD 3-Boxes Task (scaffolding). Child agency/persistence also was assessed with this task. The Social Skills Rating Scale was used to assess social competence (assertion, cooperation, responsibility, self-control). The Woodcock-Johnson-Achievement Test-3rd Edition was used to assess reading and math. Results: Child agency/persistence was related to academic achievement and support/engagement and hostility/coercion were related to child social competence. Only a few interaction effects between parenting and ethnicity were significant. Higher levels of scaffolding were related to higher scores in reading and mathematics in African American, but not in European American children. Hostility/coercion was associated with lower reading scores in European American, but not in Hispanic children. Support/engagement was related to higher levels of responsibility in both European American and African American children, but this relation was stronger in European American families. Conclusions: There are more similarities than differences in the effects of parenting and child variables in different ethnic groups. Higher levels of scaffolding are related to higher reading and math achievement in African American families; thus strategies to increase parental scaffolding may be effective in decreasing the "achievement gap."