Self-compassion refers to a positive and healthy self-attitude in times of distress and life difficulties. Abundant research has shown that self-compassion robustly contributes to adolescents’ psychological well-being. Recent research has begun to discuss the interpersonal and social benefits of self-compassion. This study examined whether and how self-compassion would be longitudinally associated with two significant other-oriented constructs: gratitude and prosocial behavior. Using a three-wave longitudinal design, a large sample of Chinese adolescents (Time 3, N = 1026; Mage = 14.41, SDage = 0.59) was measured annually at three time points. We employed both a cross-lagged panel model (CLPM) and a random intercepts cross-lagged panel model (RI-CLPM) to investigate the longitudinal associations between self-compassion, gratitude, and prosocial behavior at both between-person and within-person levels. Both the CLPM and RI-CLPM suggested that self-compassion positively predicted gratitude and prosocial behavior over time. The CLPM indicated that gratitude and prosocial behavior were bidirectionally related to each other at the between-person level, while the RI-CLPM did not find a significant longitudinal association between them at the within-person level. Also at the between-person level, the CLPM further suggested that gratitude mediated the longitudinal relation between self-compassion and prosocial behavior, while prosocial behavior mediated the relationship between self-compassion and gratitude. This study enriches understanding of the adaptive functions of self-compassion for adolescents’ social development. Self-compassion is not selfish but rather enhances feelings of gratitude toward other people and promotes the development of prosocial behavior.