The goal of this longitudinal study was to examine developmental trajectories of emotional school engagement among Chinese elementary school children. In addition, we sought to explore the role of early peer relationships and academic achievement as predictors of these trajectories. Participants at the outset of the study were N = 1,136 second-grade students (582 boys; M[subscript age] = 8.59 years) in mainland China. At Time 1, peers provided nominations of peer preference and victimization, and teachers rated children's academic achievement. Longitudinal data on self-reported emotional engagement were then collected annually for four years. Among the results, two distinct trajectories of emotional school engagement were identified: High-Decreasing and Low-Increasing. Children at Time 1 with more positive peer relationships and higher academic achievement were more likely to be in the High-Decreasing trajectory. Children with higher academic achievement also displayed a more rapid decrease in their emotional engagement in the High-Decreasing subgroup and a lower increase in their emotional engagement in the Low-Increasing subgroup. Results are discussed in terms of the implications of emotional engagement in the Chinese cultural context.