Since the early 1990s, managers of public organizations in Quebec have integrated and improved their project management processes and tools using the different PMBOK® editions. However, little research has focused on whether this framework meets public sector employees’ needs. In this context, little research has also focused on whether ISO 21502 could be a more appropriate reference for the needs of public project managers. Despite theoretical and managerial advances in project management, public sector managers and project team members still face challenges. This qualitative and descriptive case study attempts to answer three questions: What are public sector organizations’ current project management challenges? Does the Project Management Body of Knowledge meet the needs of these public managers? Could the ISO 21502 standard be a more appropriate reference to address the needs and challenges of public managers? The discussion of the results will outline the needs, challenges, and lessons learned by the employees and project managers of the public organization. Finally, we suggest that the PMBOK® is useful for managers and the ISO 21502 standard for project team members.