Purpose: The purpose of this study is to reveal the influence mechanism of social innovation education (SIE) on sustainability learning outcomes and analyze the roles of intrinsic learning motivation and prosocial motivation. Design/methodology/approach: A sample of 322 undergraduates from one higher education institution in Tianjin was used to test the hypotheses. Findings: This study found that SIE positively affected sustainability learning outcomes, and intrinsic learning motivation mediated the relationship between them. The results showed that prosocial motivation positively moderates the positive effect of SIE on intrinsic learning motivation and the overall mediation model. Practical implications: The findings have important practical implications for higher education institutions to carry out SIE. Higher education institutions should focus on integrating social innovation and sustainability into top-level design. Furthermore, higher education institutions should focus on stimulating students' intrinsic learning motivation and cultivating their prosocial motivation. Originality/value: This study identified the relationship between SIE and sustainability learning outcomes and clarified the influence mechanism of SIE on sustainability learning outcomes. Moreover, this study emphasized the importance of prosocial motivation as a key boundary condition of SIE.