Ecological approaches to preschool assessment, which consider both within-child and environmental variables, are considered best practice for school psychologists. This study employs such a model to investigate the interactive influence of child temperament and student–teacher relationship quality on peer play behaviors. Parents of 44 preschool children (25 girls, 19 boys) ranging in age from 40 to 68 months (mean [M] = 53.00) and primarily White (92.9%) provided ratings of their children's temperaments on the Behavioral Style Questionnaire. Their teachers completed the Student–Teacher Relationship Scale and the Penn Interactive Peer Play Scale. Results indicate that (a) student–teacher relationships characterized by low conflict and low dependence are associated with less disruptive peer play, and (b) the association between temperament and disruptive play is attenuated in low conflict student–teacher relationships. Implications for school psychologists include the importance of student–teacher relationships in the context of preschool assessment and intervention planning. © 2009 Wiley Periodicals, Inc.