PurposeDigitalization presents both opportunities and challenges for collaborative innovation within supply chains (SCs). Based on resource dependence theory (RDT), this study examines the underlying mechanisms of digitalization and innovation performance, elucidating the mediation and moderating role of interfirm IT integration and relational norms in the above relationships.Design/methodology/approachHierarchical regression analysis is used to test the model from 170 buyer-supplier dyads in China.FindingsThis study's empirical findings demonstrate that digitalization has an inverted U-shaped relationship with innovation performance in buyer-supplier relationships (BSRs), and interfirm IT integration partially mediates this relationship. Specifically, digitalization has an inverted U-shaped relationship with interfirm IT integration, and interfirm IT integration positively affects innovation performance. Finally, relational norms moderate this inverted U-shaped relationship, making it steeper.Originality/valueThis study embeds the impact of digitalization on innovation performance within SC relationships. By using the buyer-supplier dyad as the analysis unit, the study reveals that digitalization brings both benefits and risks to innovation performance in BSRs. Furthermore, by clarifying the role of interfirm IT integration and relational norms, the study uncovers the mediating mechanisms and boundary conditions in this relationship, thereby enriching the understanding of SC digitalization.