Enterprise architecture (EA) is a popular approach to driving digital transformation in the public sector. Implementing EA is viewed as important in facilitating the adoption of innovative technologies and new business models. However, public sector organizations have so far been unable to gain any significant benefits from EA programs. Recent reports from the Organisation for Economic Co-operation and Development and the Norwegian Productivity Committee have pointed to health and education as sectors with significant potential for improved effectivity and efficiency. The health sector in particular suffers from poor coordination among units. In this study, we aim to provide an understanding of the central challenges for organizational acceptance of EA projects in the Norwegian public sector. We conducted three case studies in 18 enterprises and divisions in the health, higher education, and labor and welfare sectors. We find three major challenges for the EA initiative, involving the autonomy of the organizational units, the national objectives that are not followed up with financial initiatives, and the lack of understanding of EA and holistic thinking. We also illustrate how institutional theory can be used to offer insights into the EA implementation process. Keywords: Enterprise architecture, Institutional theory, Public sector