This longitudinal study examined the interactive effects of individual- and classroom-level teacher−child relationships on developing externalizing, internalizing, and prosocial behaviors in kindergarten children over time. On two occasions separated by about 1 year, data were collected from 473 kindergarten children (52% boys, Mage = 4.36 years) and their class teachers and mothers in Hong Kong, China. Class teachers reported the closeness and conflict in their relationships with each participating child of their class at Time 1, and mothers reported the child’s externalizing, internalizing, and prosocial behaviors at Times 1 and 2. Results indicated that controlling for child age, gender, grade, maternal education, and prior levels of child adjustment, individual-level teacher−child closeness was negatively associated with internalizing behaviors, and individual-level teacher−child conflict was positively associated with child externalizing behaviors over time. Classroom-level teacher−child closeness and conflict emerged as moderators. The longitudinal association between individual-level teacher−child closeness and externalizing behaviors was negative in low-closeness classrooms but not in high-closeness classrooms. However, the longitudinal association between individual-level teacher−child conflict and child prosocial behaviors was negative in low-conflict classrooms but not in high-conflict classrooms. Despite the statistical significance of the cross-level interaction effects, they were of small effect sizes and explained only very small amounts of variance. Theoretically, our findings demonstrated the interplay of the individual- and classroom-level teacher−child relationships in shaping children’s psychosocial adjustment over time. Practically, our findings highlighted the importance of enhancing teachers’ awareness of the affective quality of their relationships with children at both classroom and individual levels, which could potentially impede or promote