This research discusses the existing marketplaces in Indonesia. The purpose of this research is to determine the effects of Social Influence on Behavioral Intention and Perceived Usefulness on Attitude in a marketplace. This study is quantitative research with a causal design, with 304 respondents from Surabaya. There are 9 variables in this study, namely Perceived Usefulness (PU), Perceived Enjoyment (PE), Perceived ease of use (PEOU), Trust in the mvendor (TR), Social influences (SI), Satisfaction (SAT), Usage behavior (USE), Behavioral intention (BI), and Attitude (ATT). The results show that Social Influence has a positive effect on Behavioral Intention, while Perceived usefulness is not proven to affect Attitude.