Significant attempts have been made by national governments in recent years to provide services and information on the Internet using information and communication technology. However, the accomplishment of these efforts strongly depends on how the targeted users, such as citizens, relay, use and adopt them. As a consequence, a common need to understand the adoption and diffusion of electronic government, or e-government, has emerged in both developed and developing countries. Several impediments may prevent citizens from adopting e-government services, however, and trust is one of the major barriers. Therefore, this study aims to understand the influence of citizens' trust on the adoption of e-government services in the example of Saudi Arabia. From the data analysis, the exogenous variables of trust in Internet, government ability, government benevolence and integrity, and social influence were found to significantly affect citizens' trust in e-government services, whilst citizens' trust propensity was found to more usefully predict citizens' behavioural intention to use e-government services.