This study sought to test whether teacher self-efficacy relates to child internalizing and externalizing problems over two years. For two nationally representative samples of 8-year-old Australian children (sample 1, n = 3176; sample 2, n = 3417), teachers provided information on self-efficacy, child internalizing and externalizing problems, and perceived student academic performance. After controlling for child and teacher sociodemographic factors, results showed that higher self-efficacy was associated with lower levels of child internalizing and externalizing problems, and greater mean-level decreases in internalizing and externalizing problems over two years. Self-efficacy effects were moderated by teaching experience such that self-efficacy predicted child internalizing and externalizing problems for teachers with low or moderate teaching experience, but not those with high teaching experience. There was also a significant moderation effect on child academic performance, such that higher teacher self-efficacy predicted higher academic performance, but only for teachers with low levels of teaching experience. Moderated-mediation models further demonstrated that child externalizing problems mediated the association between teacher self-efficacy and student performance for teachers with low and moderate levels of teaching experience. Overall, these findings provide evidence that, for less experienced teachers, teacher self-efficacy might have an important role in child emotional and behavioral problems.