Although green supply chain integration (GSCI) has received wide attention, how it diffuses among supply chain members to affect the manufacturer's performance is still unclear. This study examines the relationships among GSCI, information sharing, and financial performance from a social contagion lens. By conceptualizing GSCI into three forms, two types of contagion mechanisms (i.e., cohesion and structural equivalence) were identified to investigate the underlying contagion effects between different forms of GSCI and the effects of various GSCI on information sharing and financial performance. Survey data were collected from 206 Chinese manufacturers and analyzed using structural equation modeling to test hypotheses. The results indicate that green supplier integration directly promotes green internal integration, green customer integration, and information sharing with suppliers. Green internal integration positively influences green customer integration and financial performance.Green customer integration enhances information sharing with customers. Both information sharing with suppliers and customers improve financial performance. This study contributes to the GSCI literature and provides novel managerial implications for manufacturers.