This study aims to investigate the relationship between social dominance orientation (SDO) and subjective well-being among Chinese adolescents (N = 4246), and to examine the mediating role of prosocial behaviour in this relationship. The structural equation model's results showed that SDO was negatively associated with prosocial behaviour and subjective well-being, that prosocial behaviour was positively associated with subjective well-being, and also that (low) prosocial behaviour partially mediated the negative relationship between SDO and subjective well-being. Multi-group analyses showed that the mediation model was generally similar between boys and girls, but that the negative relationship between SDO and prosocial behaviour was somewhat stronger among girls than boys. This study sheds light on how SDO is associated with positive outcomes among Chinese adolescents and highlights the mediating role of prosocial behaviour as an underlying mechanism between SDO and subjective well-being. Future studies are needed to further discover the role of culture values in the association between SDO and subjective well-being.