With the emergence of Internet applications, online shopping has become a part of our daily life. In recent years, group-buying platforms have emerged all over the major economies, and group buying has become one of the most famous business models on the Internet. To enable the group buying transactions, the service qualities are very critical. However, very few researches focused on this topic. Therefore, this research aims to introduce the E-Service Quality (E-SQ) analytic model as the basis. The analytic framework will be constructed by using the decision making trial and evaluation laboratory (DEMATEL). Then, the influence relationships and the weights being associated with the criteria will be derived by using the DEMATEL based network process (DNP). The managers from Taiwanese group buying companies will be invited to serve as experts. According to the empirical study results, the causal relationships being derived by the DEMATEL and the DNP demonstrate the direct influence of the Security and Reliability dimensions on others. Additional, based on the influence weights being derived, the Website Appearance, Efficiency and Access are the most important dimensions.