Disparities in health and achievement are greater for low income ethnic minorities. There is a growing evidence base that supportive teacher-child relationships are associated with positive socioemotional outcomes and can act as a protective factor for children, including those at risk for poorer outcomes due to their racial/ethnic backgrounds and socioeconomic status. Research suggests that the reverse is also true. Specifically, children’s behaviors can also reciprocally impact the quality of teacher-child relationships. While there is an abundance of research on associations between the teacher-child relationship and child outcomes in school-aged children, this is one of the first studies to focus on these associations in a low-income, ethnically diverse population of preschoolers. In the current study, data on preschoolers (N = 2152) and their teachers (N = 229) were gathered during the beginning and end of the preschool year in the context of a larger study evaluating a kindergarten readiness program (Baker, Kupersmidt, Voegler-Lee, Arnold, & Willoughby, 2010). Teachers completed questionnaires about preschooler social skills, inattention, and oppositional/defiant behaviors. Project staff conducted assessments of preschooler behavior regulation and also gathered information about the teacher-child relationship using observational measures. The influence of teacher-child relationships on preschooler functioning was examined using hierarchical linear modeling. The influence of preschooler functioning on teacher-child relationships was analyzed using linear regression. Results indicate that teacher-child relationships established early in the preschool school year impact preschooler social skills, behavior regulation and oppositional/defiant behaviors later in the same school year. Additionally, behaviors exhibited by preschoolers early in the year appear to influence the levels of sensitivity and permissiveness in teacher-child relationships later in the year. These reciprocal relationships were also moderated by preschooler age, gender and race/ethnicity. Limitations of the study and implications of the findings as they relate to the professional development and training of professionals in preschool settings are also described. / acase@tulane.edu