We investigated the effect of playfulness on user acceptance of online retailing and tested the relationship between Web quality factors and user acceptance behavior. A survey of 942 users of Web-based online retailing was conducted to test our model. The results showed that playfulness plays an important role in enhancing user attitude and behavioral intention to use a site. We also found that Web quality, categorized into system, information, and service quality, had a significant impact on the perceived case of use, playfulness, and usefulness, and consequently, that it encouraged website use in the context of online retailing. Our study thus provided a balanced and integrative framework for determining Web quality. It enhanced our knowledge of the effect of playfulness, which should help Web practitioners and researchers better understand user behavior in Web-based online retailing. (C) 2007 Elsevier B.V. All rights reserved.