The current study reports the results of a randomized controlled trial examining the impact of the Getting Ready parent engagement intervention on young children’s social–emotional competencies and the quality of the student–teacher and parent–teacher relationships. Participants were 267 preschool-aged children and their parents, as well as 97 preschool teachers. All children attended publicly funded preschool programs and were low income. In addition, all were considered educationally at risk due to developmental concerns in the areas of language, cognition and/or social–emotional development. Parent and teacher surveys were administered twice per academic year (fall and spring) for two academic years. Findings indicated that children in the treatment group were rated by their teachers to have greater improvement in social skills over two years of preschool as compared to their peers in the comparison condition. Teachers in the treatment condition reported significantly greater increases in their relationships with children as compared to children in the comparison group. Teachers in the intervention group also reported significant increases in their overall relationships with parents. The current findings illustrate the efficacy of Getting Ready at improving the social skills and important relationships for preschool children experiencing developmental risk. (author abstract)