Although a small body of research suggests that emotional engagement with school is related to youth behavioral and psychological outcomes, it remains unclear whether these associations represent causal relationships and at what age engagement matters most for student outcomes. Using data from two large, national surveys, this study uses three analytic strategies to reduce threats to causal inference and assess whether the central relationship changes as youth age. Results across both data sets are consistent with a causal relationship between emotional engagement with school and youth behavioral and psychological outcomes that decreases somewhat as youth age. Given the importance of emotional engagement for these outcomes, and the importance of avoiding problem behaviors and maintaining healthy psychological functioning for students' long-run outcomes, research should continue to explore the ways in which schools and educational policy can influence students' engagement.