Numerous models of IS success and technology acceptance their extensions have been proposed and applied in empirical. This study continues this tradition and extends the body of knowledge on the topic of IS success by developing a more comprehensive model for measuring IS success and technology acceptance within a government organization. The proposed model builds upon three established IS success and technology acceptance frameworks namely the DeLone and McLean (2003), Venkatesh et al.'s (2003) unified theory of acceptance and use of technology (UTAUT), and Wixom and Todd (2005). The findings from this study provide not only a comprehensive IS success assessment model but also insights into whether and how IS success models are influenced by application variables as applied within a government organization. Exploratory factor analysis and confirmatory factor analysis were performed for instrument refinement and validity test of the existing and proposed models. Using data from employees of a local government municipal, the comprehensive model explained 32 percent variance. Four of the hypothesis were fully supported five were not supported, and four were partially supported. In addition, the results suggest that behavioral intention may not be the best predictor of technology acceptance in a mandatory environment.