Previous studies have shown that adolescents are experiencing growing pains due to their unbalanced physical and mental development. Their life satisfaction showed a steady downward trend with age. Altruism may be an effective way to improve their life satisfaction. Against this background, the current study carried out school altruistic group games for the first time to explore the role of altruistic group activities in the school context in improving adolescents’ life satisfaction. There were 176 adolescents in the study, including 90 (...) in the experimental group and 86 in the control group, who were enrolled from a junior high school in East China. A 10-week school altruism group game was carried out for the experimental group. The participants in the control group participated in activities that were not related to altruism. Participants in both groups reported their life satisfaction and emotions before and after the games. The findings of this study were as follows: SAGGs can effectively improve adolescents’ life satisfaction, especially school satisfaction; SAGGs can significantly improve adolescents’ emotional state; that is, SAGGs can enhance positive emotions and reduce negative emotions; and SAGGs have different effects on the life satisfaction of adolescents with different initial emotional states. The results of this study not only enrich the existing literature but also provide enlightenment and a reference for schools to improve adolescents’ life satisfaction. (shrink)