Shame is commonly conceptualized in extant research as a self-conscious emotion or a disposition to experience it (i.e., shame proneness). This study introduces a distinct concept of shame, termed sense of shame, defined as a dispositional propensity to refrain from experiencing shame. Individuals with a strong sense of shame proactively monitor their thoughts, words, and behaviors against internalized standards, rules, and goals, thereby eschewing from transgressions that would elicit shame. It is posited that this sense of shame would promote altruistic tendency, as helping others represents an internalized social norm that individuals are motivated to uphold. To test this proposition, a two-wave longitudinal study with a one-year interval was conducted among 319 undergraduate students (Mean age = 18.47; 16.3% male, 83.7% female), who completed questionnaires assessing sense of shame and altruistic tendency. Cross-lagged panel analysis revealed a bidirectional relationship: sense of shame at Wave 1 positively predicted altruistic tendency at Wave 2, and altruistic tendency at Wave 1 positively predicted sense of shame at Wave 2. These findings provide empirical support for the adaptive function of sense of shame and deepen our understanding of its role in cultivating stronger altruistic tendency, while altruistic inclinations, in turn, further consolidate sense of shame. Together, they underscore a positive feedback loop that sustains a dispositional orientation toward altruism over time. This suggests that enhancing either sense of shame or altruistic tendency may strengthen the other, yielding promising avenues for educational and community interventions that cultivate a healthy sense of shame. Such interventions can foster moral self-monitoring and self-regulation, providing a practical route to advance shared flourishing through collective well-being sustained by mutual care and prosocial cooperation in applied settings.