Whereas social support contributes to individual vitality and academic performance, the theoretical process through which social support promotes performance, and for whom it is most beneficial in this respect, remain open questions. We developed a conceptual model in which social support influences academic performance by promoting vitality, particularly among individuals who are low on social self-efficacy (SSE). Social support has a positive effect on university students' academic performance, which is largely explained by its relationship with reported vitality among students with relatively low levels of SSE but not among students with higher SSE. We discuss the theoretical and practical implications for the existing literature on social support and vitality in academic settings.