Background and purpose: Lack of learning motivation, large amount of information that must be learned in a short time, and lack of up-to-date content are among the limitations of effective learning. Flipped learning is suggested as a solution in which direct teaching in classroom environment is replaced by teaching and individual learning using educational tools and technologies. In this study, we investigated flipped learning process in Mazandaran University of Medical Sciences, aiming in-service training of employees, 2020. Materials and methods: A qualitative study using grounded theory approach was performed. The participants (n=16) included elite university experts and members of the education and empowerment committees in Mazandaran, Babol, and Tehran universities of medical sciences. They were selected via purposeful sampling. In-depth interviews were done and data were analyzed by MAXQDA 2018. Results: Flipped learning process in Mazandaran University of Medical Sciences has 12 dimensions, including learning motivation, individual factors, factors of organizational culture, structural factors, establishment of flipped learning, facilitating measurements, organizational barriers and challenges, non-organizational barriers and challenges, planning, awareness, the quality of education, and learning quality. Conclusion: Acknowledging flipped learning, as an independent approach, by senior managers, providing and improving the quality of e-learning infrastructure and facilities, and improving management capabilities and performances through recruiting professors who are familiar with this phenomenon can be of great benefit in implementing this approach.