Incubator tenants usually lack established business relationships and legitimacy. Incubators, therefore, aim to aid tenants in forming meaningful relationships that will contribute to their development. The literature on incubator tenants, including their development, naturally focuses naturally on when they are in an incubator. Valuable insights have been made on how network-based incubation influences the performance of tenants. However, the relationship between networks and performance is ambiguous, and the choice of measure plays an important role. Gradation is a clear indicator of venture development in an incubator. Nonetheless, few studies have focused on the impact of tenants’ relationships on graduation. This study focuses on the impact of social capital on the graduation of incubator tenants. It explores how tenants’ relationships impact their graduation by investigating the collective and individual social capital of tenants. A structural equation model was employed to study the impact of social capital on graduation based on data from incubators in the Wuhan Donghu High-Tech Zone. This study’s contributions are as follows: first, it provides insights into the impact of bonding and bridging social capital on tenants’ graduation. Second, it sheds light on the different roles of the collective social capital of incubators and individual social capital of tenants and their contributions to tenants’ graduation. Third, it provides a description of the heterogeneous mechanisms of individual social capital of tenants and their association with graduation.