Despite the importance of knowledge exchange among participating firms in enhancing the effectiveness of the entire supply chain, cases of effectively utilizing knowledge held by partner firms are extremely rare. A literature review reveals that two opposing forces simultaneously operate around inter-firm knowledge exchange: (1) firms seek to exchange knowledge with supply chain partners from a social capital perspective, while (2) they also seek to maintain a certain degree of knowledge/information asymmetry to counter the opportunistic behavior of trading partners. Therefore, research is needed on when the social capital perspective emphasizing inter-firm relationships prevails to facilitate knowledge exchange, and when the transaction risk perspective prevails to inhibit knowledge exchange. In this study, based on existing literature, the context of inter-firm relationships—namely, upstream supply chain relationships versus downstream supply chain relationships—was identified as the key contingency factor. To test the hypotheses proposed in this study, data were collected from firms serving as intermediate producers in the domestic electronic components industry. In the upstream supply chain relationships, 82 firms participated, while 80 firms participated in the downstream relationships. In the upstream supply chain relationship sample, as predicted, the social capital perspective measured by inter-firm trust had a significant effect on knowledge exchange, while the risk of partner opportunistic behavior did not have a significant effect. In the downstream supply chain relationship sample, neither the social capital nor the transaction risk perspectives had significant effects. The academic and practical implications of these findings were also discussed.