The current context shows an increase in the attraction to online purchases on retail websites. Hence, there is a change in the behavior of millennial users and the factors that seek their purchase intention. Therefore, the objective of this study is to analyze the effect of WE factors (usability, interactivity, trust and aesthetics) on the OPI of users on retail websites, specifically in the clothing category, in Lima Metropolitan. The study’s findings would aid retailers in designing more effective websites. From 486 questionnaires distributed to millennials in Lima Metropolitan, 400 effective responses were obtained. Likewise, non-probability sampling was used with a convenience sampling technique. The collected data was processed using SPSS. Cronbach’s Alpha was used to check the reliability of the scales. An exploratory factor analysis was performed for data reduction that allowed exploring the variables under study. Finally, a multiple linear regression was performed to determine the relationship structure between the variables. The results show that usability, interactivity, trust and aesthetics are the WE factors that positively and significantly affect online purchase intention in millennial users in Lima Metropolitan. 4 hypotheses were proposed which were fully accepted. This research shares relevant information about the effects of WE factors on OPI. It expands the knowledge regarding the importance of effective website design by integrating the most relevant factors such as usability, interactivity, trust and aesthetics to improve the WE.