Vietnam is recognized for its significant growth in e-commerce. Shopee has become the leading e-commerce platform in Vietnam in terms of revenue and market share. However, Shopee Vietnam faces several challenges, including how customers perceive its services. There is also a lack of academic studies on how the COVID-19 pandemic affected consumer buying habits, especially in relation to Shopee Vietnam. This research looks into how the quality of Shopee's website - including its system, information, and service quality - affects customer buying behavior. The study uses a theoretical framework and tests ten hypotheses using a quantitative approach. Data was collected from 309 Shopee users through a questionnaire and analyzed with SPSS and AMOS 22.0 software. The results show that only information quality and system quality significantly influence customer buying behavior, with service quality having no notable effect. Information quality is the most influential factor. The study concludes that customers view Shopee.vn not just as a place to buy, sell, and ship goods but also as a source of information for searching, exploring, and comparing data.