The objective of this paper is to gain a better understanding of the driving forces in enterprise systems (ES) implementation in the public sector by providing a conceptual framework that illustrates these driving forces and their interrelationships. ES in the public sector may improve operational efficiency, provide more timely access to data for public decision makers, lead to more and better information for the community, and thus may have a substantial impact on socio-economic development. Though there has been much research on ES implementation in the private sector, the findings from the private sector do not always carry over to public organizations, which differ substantially from private companies in external regulations, available resources, and internal culture. The data in this multi-case study were collected in semi-structured interviews of City Hall employees in Poland, representing diverse levels of experience and authority. Based on these data, we identify six key concepts in ES public sector implementations and propose a conceptual framework to serve as guidance for future ES implementation projects in the public sector as well as provide a foundation for future research.