The pension system of different countries has witnessed developments in recent decades towards development of the multi-pillar systems and introduction of private pension funds as a complement to public pension funds. Each country has specific regulatory structures and frameworks in place for the establishment and operation of these institutions, but in our country their legal structure and specific legal frameworks have not been defined. Therefore, in this article, using an analytical-descriptive method and library research, the characteristics and features of the discussed funds have been examined, and the question of what the legal framework and regulatory provisions of private pension funds should be is answered. In response, considering their independent legal personality and supervisory transparency, a structure similar to the institutional structure of stock exchange investment funds, provided certain shortcomings such as institutional deficiencies in the structure and functioning of the pension system's governing board are addressed, can provide a suitable structure for private pension funds. On the other hand, selecting a specific participation framework can minimize legal risks related to property ownership, maintain the relationship between participation, benefits, and justice at individual and generational levels, and ensure the property rights of the pension community's stakeholders. The governmental supervisory authority must also be independent, with sufficient legal authority, and operate under the Supreme Council of Welfare and Social Security. Additionally, the development of specific and comprehensive regulations with appropriate enforcement mechanisms should clarify the rights and responsibilities of various components of the pension fund market and address the inefficiencies of contractual obligations established in the form of prospectuses or statutes.