Background: In-service training is one of the requirements for developing health Workforce skills and providing quality services to patients. Objectives: This study aimed to determine the policy formulation of in-service training for the health Workforce in Iran. Methods: In this qualitative policy analysis study, semi-structured interviews with key informant persons and document analysis were used to gather data. Interviews were conducted with 12 informed people about health system policies, experts, andmanagersof in-service training centers of medical universities and the Ministry of Health and Medical Education (MOHME) selected purposively. Targeted and snowball sampling was used to identify the participants. Data analysis was performed using the MAXQDA10 software, and framework analysis was run using the Kingdon model. Results: Centralized planning, lack of access in rural and remote areas, and the inability to use the potential of universities in staff training were the most frequent problems in in-service training of the health Workforce. Establishing the Board of Trustees for universities affected the opening of the opportunity window to policy-making, and political entrepreneurs in MOHME took advantage of it and developed policies for in-service training. Conclusions: The Development of policies has created a suitable platform for medical universities to increase the number of training hours and develop the skills of the health Workforce. It also seems that policymakers’,attention can lead to improving processes and using new approaches in the continuous Development of health professions.