As a type of online shopping, online group-buying is inherently affected by consumers' social interaction. In the context of group-buying, consumers can be affected by other group members who share information and communicate with them online. Previous researchers have found that in an online environment, trust can significantly influence consumers’ purchase intentions. Therefore, in this paper we study social interaction factors that affect consumer trust in the context of online group-buying in China. The results of this empirical study of online group-buying in both product and service contexts indicate that social interaction has significant informational and normative influences on consumer trust. However, informational influence affects consumer trust more in service contexts, whereas normative influence affects trust more in product contexts. Moreover, the results of the study show that the valence of comments (i.e., positive or negative) does not significantly impact how informational influence and normative influence affect consumer trust in the online group-buying context.