In a network economy environment, inter-firm cooperation is crucial for business success, and a core element of such cooperation is information sharing between firms. Accordingly, inter-firm information sharing within supply chains has been a subject of interest across many fields of research. However, empirical studies on inter-firm information sharing and supply chain performance remain extremely scarce. This study identified the determinants of the level of electronic information sharing among supply chain participants and examined inter-firm electronic information sharing and relative absorptive capacity as factors influencing supply chain performance. The results showed that inter-firm task interdependence, product complexity, and inter-firm information technology infrastructure had statistically significant effects on electronic information sharing. Additionally, relative absorptive capacity was found to directly influence supply chain performance and also to indirectly influence it through inter-firm electronic information sharing. However, contrary to the research hypotheses, the effects of inter-organizational trust on inter-firm electronic information sharing and supply chain performance were not found to be statistically significant. The findings of this study suggest that inter-firm electronic information sharing within supply chains serves as an important mediating variable between inter-firm information technology infrastructure and supply chain performance.