Drawing on prospect theory, this study examines the reference-point effect of ESG performance on corporate collaborative innovation and its underlying mechanisms. Using data from A-share listed fi rms in China between 2009 and 2023, the findings show that a firm’s ESG performance relative to its peers is positively associated with collaborative innovation. Specifically, ESG performance below the reference point inhibits collaboration, while performance above the reference point promotes it. Mechanism tests indicate that relative ESG performance aff ects collaborative innovation through two channels: The collaborative innovation network and resource allocation efficiency. The heterogeneity analysis further shows that this effect is mainly concentrated in state-owned enterprises and fi rms in less competitive industries. Further analysis reveals that fi rms’ risk-taking capacity weakens, while external media attention strengthens, the reference-point effect of ESG performance on collaborative innovation. Overall, the study highlights the existence of an ESG reference-point eff ect in collaborative innovation, suggesting that maintaining an ESG advantage helps fi rms avoid marginalization within innovation networks.