Geographic information systems (GIS) have become a fact of our life as they are being used by more people and organizations for more complex decision problems than ever before. The use of GIS can achieve valuable benefits for individuals, organizations and society; however, the achievement of these benefits depends on the success of GIS. While information systems (IS) success models have received much attention among researchers, there is a general scarcity of research conducted to measure the GIS success. This study proposes a comprehensive multidimensional success model for measuring GIS success by extending and modifying previous IS success models. In this model, we have tried to improve the previous IS success models by providing a holistic view of GIS success concept via defining GIS success as a cumulative process that starts from initiating successful GIS projects and ending with the success of GIS in delivering their business objectives. Thus, the proposed success model consists of two main levels; GIS project diffusion success, and GIS post implementation success. The first level of the proposed GIS success model identifies the critical success factors (CSFs) that influence the success of GIS adoption at each stage of the diffusion process. The second level of the proposed model identifies the success dimensions (outcome measures) of GIS. These dimensions include system quality, user quality, information quality, information use, user satisfaction, and net benefits to individuals, organization, and society. In order to validate the proposed model, eleven hypotheses were tested. Data collected through a questionnaire that was distributed to 252 GIS users and managers in Egypt and abroad. Data was processed through Statistical Package for the Social Science (SPSS) and Linear Structural Relations (LISREL) software. The empirical results support six hypotheses and reject five hypotheses.