Research Findings: Parental engagement with children has been linked to a number of adaptive characteristics in preschool children, and relationships between families and professionals are an important contributor to school readiness. Furthermore, social-emotional competence is a key component of young children's school readiness. This study reports the results of a randomized trial of a parent engagement intervention (Getting Ready) designed to facilitate school readiness among disadvantaged preschool children, with a particular focus on social-emotional outcomes. Two hundred and twenty children were involved over the 4-year study period. Statistically significant differences were observed between treatment and control participants in the rate of change over a 2-year period on teacher reports for certain interpersonal competencies (i.e., attachment, initiative, and anxiety/withdrawal). In contrast, no statistically significant differences between groups over a 2-year period were noted for behavioral concerns (anger/aggression, self-control, or behavioral problems) as a function of the Getting Ready intervention. Practice or Policy: The intervention appears to be particularly effective at building social-emotional competencies beyond the effects experienced as a function of participation in Head Start programming alone. Limitations and implications for future research are reviewed. (Contains 4 footnotes, 4 tables and 3 figures.)