The paper focuses on Community of Practice (CoP) in the public sector as a lever for the development of learning processes and organizational change. While existing literature suggests that CoPs may be considered as a tool for knowledge sharing and learning process, previous contributions have rarely analysed organizations in the public sector. We deal with an experience promoted by SNA (Italian School of Public Administration) to establish a community of managers specialized in staff training and belonging to different Italian public administrations. The community involved managers from all central administrations and government agencies (about forty organizations) that have cooperated for the rationalization, digitization and innovation of the programming processes of training activities for two years. Our results show that the community has facilitated learning and knowledge exchange and has helped SNA to define needs in terms of training of public servants. Our empirical study contributes to the understanding of the theoretical relationship between CoP and learning processes in the public sector, which has been neglected in knowledge management research.