This research aims to analyze and show the influence of user interface and usability on interest in using the Shopee application among Generation Z in Medan City and its surroundings. This type of research uses a quantitative approach. The population of this research is all Generation Z users of the Shopee application in Medan City, an unknown number. The sampling technique uses random sampling. The sample was measured using the Lemeshow formula, and a sample of 97 respondents was obtained. Data sources use primary data from questionnaires and secondary data from articles, books, and websites. The SmartPLS 3.0 application assisted the data processing process carried out by researchers with structural equation model (SEM) analysis techniques. The research results show that the user interface positively and significantly influences interest. Usability also positively and significantly influences interest. Theoretically, this research contributes to refining existing theories. Practically, it can be used as a reference for companies engaged in providing services in the form of mobile applications to pay more attention to user interface and usability factors in their systems, especially e-commerce companies, to create positive preferences among consumers to attract their interest in using the system.