E-government has become a popular focus of government efforts in many countries around the world. More and more governments around the world are introducing e-government as a means of reducing costs, improving services, saving time and increasing effectiveness and efficiency in the public sector. E-government and the Internet has made an essential change to the whole of Saudi societal structure, values, and culture, as well as the ways of conducting business by utilizing the potential of ICT as a tool of daily work. Therefore, e-government has been identified as one of the top priorities for Saudi government and all its agencies. However, the adoption of e-government faces many challenges and barriers, including political, cultural, organizational, technological, and social issues which must be considered and treated carefully by any government contemplating e-government adoption. Findings of several studies indicate that despite the high cost of e-government projects, both tangible and intangible, many e-government efforts are failing or are slowly diffusing. This thesis presents a comprehensive study and investigation of the influential factors on the acceptance of using e-government services (G2C) in the Kingdom of Saudi Arabia (KSA) by adopting the Unified Theory of Acceptance and Use of Technology (UTAUT) model. This study uses an amended version of the UTAUT model as its theoretical foundation. UTAUT is an empirically validated model that combines eight major models of technology acceptance and their extensions. The study investigates the effect of proposed UTAUT constructs and moderating variables on e-government services use and acceptance. Therefore, this study critically assesses key factors that influence e-government service acceptance in the public sector in Saudi Arabia, discusses the importance of citizen perspective about e-services, and provides a comprehensive assessment of e-service providers and citizens’ perceptions about the obstacles facing e-government services acceptance and use in Saudi Arabia. This thesis provide a comprehensive view and deep understanding of e-government services adoption based on the perceptions of e-services providers and Saudi citizens through the utilisation of the UTAUT model.