Online shopping is associated with various uncertain issues. In this sense, researchers have found that trust plays an important role in affecting consumers' purchase behavior. As advances of Internet technology, many consumers tend to read online messages about others' shopping experiences before making purchasing decisions. Thus, informational social influence affects in the decision-making process as well. However, few studies have provided in-depth examination of both impacts from trust and informational social influence in online context. In this study, we explore the moderating effect of informational social influence in a trust-based online shopping model. We conduct a laboratory experiment to verify this model, and find that emotional trust mediates relationships between three trusting beliefs (competence, benevolence, and integrity) and purchase intention. Further, information inconsistency, a particular form of informational social influence, is found to strengthen the relationship between emotional trust and purchase intention. Implications for research and practice are discussed. © 2010 IEEE.