This study aims to analyze the effect of service quality, brand image, price perception on trust and purchasing decisions on the E-commerce platform Zalora.co.id. the development and progress of E-Commerce has become common in the community, the facilities available make this platform has an increasing demand in all market segments. From the ease of access to the speed of E-commerce services is an attraction for consumers. Service Quality, Brand Image, Price and Product Trust are widely used as a reference for consumers in Indonesia to determine purchasing decisions. In this study data were collected from 182 selected respondents who had made purchases on the E-commerce platform Zalora.co.id and were at least over 17 years old. The technique determined in sampling is using non-probability sampling with a purposive sampling method and distributing questionnaires using Google Forms. The analytical tool used is Structural Equation Modeling (SEM) with the AMOS 22 application program. The results of this study indicate that Service Quality, Brand Image, Price Perception has a positive and significant effect on product trust. Trust acts as a mediating variable that has a positive influence on purchasing decisions.