The religious factor and endowments are two significant elements that have profoundly influenced the fundamental structure of Islamic cities, especially in Iran. Among various forms of charitable giving aimed at urban development in these cities, endowments are particularly beneficial. Currently, city management and development are guided by urban development plans that help managers construct a desirable long-term vision for their cities. This research aims to provide an explanatory framework regarding the role of endowments in urban development plans from an institutionalist perspective in Iran. To achieve this goal, the research follows four steps: In the first step, relevant articles and theses related to the research topic are identified and reviewed. The second step involves examining the position of endowments within the classification of institutions. In the third step, both formal and informal endowment institutions are identified. Finally, the impact of these institutions on the preparation, approval, and implementation stages of urban development plans is analyzed. This research is qualitative in nature and is based on a systematic analysis of existing studies, categorizing it as a meta-analysis. It is also considered an applied research study due to its practical applications. The findings suggest that the concept of endowment initially emerged as a series of norms and religious customs, which gradually evolved into a formal institution that falls under the category of governing institutions. While formal institutions may seem more significant at first glance due to their legal and executive backing in various stages of urban development plans, the influence of informal endowment institutions should not be underestimated. Consequently, both formal and informal institutions play vital roles in various phases of development plans, as indicated in a conceptual framework.