e-Government (e-Gov) projects are continuing to fail in countries across the world, including South Africa. Therefore, although e-Gov presents a means to transform government service delivery to citizens, the intended benefits are not achieved. In addition, the failure of e-Gov leads to significant wasteful expenditure. This paper focuses on a specific category of e-Gov, Governmentto-Government (G2G), concerned with the use of Information and Communications Technology to automate and streamline business processes within a government department and across departments. Challenges facing user adoption of G2G in a South African context are analysed using the KwaZulu-Natal Department of Transport as a case study. As the first step in this research, cases of G2G user adoption challenges in South African government were identified. This helped inform the focus of the literature review and the research instrument used. A qualitative research methodology was used to understand the G2G user adoption challenges. This research has shown that user adoption is a central challenge facing G2G. User adoption is influenced by six main themes: Addressing User Requirements, Business Process Management, Change Management, User Involvement, Organisational Culture and Priority. The six main themes in turn are influenced by subthemes: strategy, usability, complexity, HR skills, resistance, systems development methodology, management support and data quality. Technology infra-1 This article is drawn from an unpublished doctoral thesis.