Teacher-child relationships have been linked to children's classroom engagement and to academic achievement. However, researchers have paid minimal attention to individual child factors that predict the development of these relationships. In the current study, we examined executive function (EF) prior to school entry as a predictor of teacher-child relationships at kindergarten through second grade. We also examined externalizing behavior problems, verbal intelligence, and academic achievement as mediators of these associations. Data were from the Family Life Project, a prospective, longitudinal sample of N = 1,292 families from predominantly low-socioeconomic status (SES) and rural communities in Pennsylvania and North Carolina. Children were administered a multidimensional battery of EF when they were 48 months old and standardized measures of verbal intelligence and academic achievement at prekindergarten. Parents reported on externalizing behavior problems when children were 60 months old. Kindergarten, first-, and second-grade teachers reported on teacher-child relationships. Growth curve models revealed that EF at 48 months positively predicted closeness and negatively predicted conflict with teachers in kindergarten but not change in closeness or conflict over time. Verbal intelligence mediated the associations between EF and both closeness and conflict. EF continued to significantly predict conflict, but not closeness, with kindergarten teachers when the mediator was included in the model. The results of this study are discussed in the context of the implications of children's self-regulation for classroom engagement in a low-SES sample. [This article was written with The Family Life Project Investigators.]