The study examined the mediating roles of academic buoyancy and academic emotions in the relationship between classroom social climate (CSC) and student engagement in English as a foreign language (EFL) learning. The study involved 759 Chinese university students and utilized confirmatory factor analysis (CFA) and structural equation modeling (SEM) for testing. The results showed that (1) CSC positively predicted student engagement; (2) academic buoyancy partially mediated the relationship between CSC and student engagement; (3) academic buoyancy negatively predicted foreign language classroom anxiety (FLCA); (4) foreign language enjoyment (FLE) and foreign language boredom (FLB) partially mediated the relationship between CSC and student engagement; (5) CSC predicted student engagement through the sequential mediating roles of academic buoyancy and FLE; (6) the relationships between CSC and FLCA, between FLCA and student engagement, and between academic buoyancy and FLB, however, were reported to be nonsignificant. The findings verify the contributions of positive psychology to EFL pedagogy, generate implications for EFL teaching, and offer a point of departure for future studies.