Trust has been accepted as a critical element in electronic commerce due to the fact that online transactions are characterized as a process that involves uncertainty and risk. Trust also has been thought of as the most effective means of reducing uncertainty and risk. The effect of measures to build and maintain trust in e-commerce is subject to person-specific and situation-related factors that cannot be controlled by web vendors. This study has explored a factor that influences trust during online transaction. Self-efficacy, which is an important factor in explaining motives and motivations of individual behaviors and choices, has an impact on trust building and uncertainty reduction. By incorporating self-efficacy into electronic commerce research, this study expands the understanding of what factor plays a role in reducing uncertainty. The results show that self-efficacy affects trust in the web vendor and, consequently, positively influencing the respondent's purchase intentions.