This study investigates the dynamic interplay between teacher-child relationship quality and children's behaviors across kindergarten and first grade to predict academic competence in first grade. Using a sample of 338 ethnically diverse 5-year-old children, nested path analytic models were conducted to examine bidirectional pathways between children's behaviors and teacher-child relationship quality. Low self-regulation in kindergarten fall, as indexed by inattention and impulsive behaviors, predicted more conflict with teachers in kindergarten spring and this effect persisted into first grade. Conflict and low self-regulation jointly predicted decreases in school engagement which in turn predicted first-grade academic competence. Findings illustrate the importance of considering transactions between self-regulation, teacher-child relationship quality, and school engagement in predicting academic competence.