In some countries, including Iran, the education system and curriculum are centralized. In recent years, decentralization in Iran's educational system has been the focus of officials and planners, as in other countries, and there has been a great tendency towards decentralization. During the recent years, decentralization in the education system of Iran, like other countries, has been the focus of the officials. In the current research, the reasons, opportunities and challenges of decentralization in the curriculum were analyzed.

According to the nature of the research, qualitative method of phenomenological type was used. The statistical population of the research was all curriculum planning experts. Purposive sampling of the criterion type was used, and with the in-depth interview of 7 experts in the field of curriculum planning, the obtained data was saturated. The data obtained from the perception and lived experiences of the experts were analyzed using the Colizzi analysis method at three levels of open, central, and selective coding, and MAXQDA11 software was used as a data analysis tool.

The findings of the research, which were the result of the perception and lived experiences of curriculum planning experts in the field of decentralization, were categorized into 3 main themes: "Reasons and Necessities of Decentralization", "Opportunities and Consequences of Decentralization", "Challenges and Problems of Decentralization.

The experiences of experts show that decentralization in the education system is very necessary due to the inefficiency of the centralized system, but in the meantime, the actions of the headquarters in the direction of decentralization are very sudden and cause more damage, Also, in order to decentralize, the human resources of education and training are still not qualified, and system infrastructures and change of beliefs should be done in this area.