Firms in a volatile environment often possess more chances to commit opportunistic behaviours by taking advantage of information asymmetry. Moreover, it is essential for a firm to prevent opportunism since it will increase the cost of transaction. Network solidarity plays a significant role in firm’s performance, and a wide variety of research has been conducted on uncertainty and opportunism. However, the impact of network solidarity on the relationship between behavioural uncertainty and opportunism still remains unclear. Thus, the object of this paper is to introduce how behavioural uncertainty influences opportunism of an exchange partner under conditions reflecting network solidarity. The conceptual framework highlights the relationships among those variables, and as a result, this study can offer some possible directions, and further provide theoretical and practical implications as well as suggestions for the future study.