This study examined the relations among preschool teachers' self-efficacy (n = 67), classroom quality (instructional and emotional support), and children's (n = 328) gains in print awareness and vocabulary knowledge over an academic year in the US. Results indicated that teachers' self-efficacy and classroom quality served as significant and positive predictors of children's gains in print awareness but not vocabulary knowledge. However, results also showed a significant interaction among teachers' self-efficacy, classroom quality, and vocabulary gains: for children of teachers with higher levels of self-efficacy, higher levels of classroom quality (emotional support) were associated with higher vocabulary gains. (Contains 1 figure and 5 tables.)