Online business, or E-commerce, has experienced tremendous growth in recent years. Southeast Asia has all the ingredients for a promising market-rising Internet and mobile penetration, a growing middle class with greater discretionary spending, and an increasing supply of digital platforms. Among the emerging Southeast Asia markets, E-commerce has developed vigorously in Vietnam recently. The Vietnamese government has revised regulations governing E-commerce to facilitate the country’s E-commerce development. In addition, improvements in two important infrastructural aspects, payment and delivery systems, could give a further boost to E-commerce. Due to these factors, E-commerce has attracted much domestic and foreign investment and become a competitive environment for online companies. The objective of this research is to investigate the key factors affecting consumers’ selection of online shopping websites in Vietnam. Obtaining 4 dimensions and 17 factors affecting Vietnamese consumers’ choice of online shop websites from reviewed literatures, we then designed questionnaires and randomly distributed them to respondents. Then, Analytic Hierarchy Process (AHP) was employed to analyze the questionnaires. The rank of dimensions is found to be as follows: trust, customer service, benefits, and website, while that of factors is: reputation, assurance, privacy risk, security risk, convenience, delivery time, responsiveness, after-sale service, price, usefulness, product selection, ease of use, speed, information contents, enjoyment, accessibility and website design characteristics. Finally, we propose suggestions for Vietnam online shopping websites based on the results of this research.