In many countries, population policies have shifted from quantitative, single-instrument interventions toward more comprehensive approaches. The aim of the present study is to identify the institutional architecture patterns of population policies in selected countries and implications for Iran. Utilizing documentary analysis and structured comparison, the study examines three main components: "institutional actors and their legal status," "rules governing cross-sectoral coordination," and "mechanisms for accountability, monitoring, and policy learning." The findings reveal a centralized architecture with supra-ministerial coordination linked to the resource allocation process; a decentralized architecture based on the division of responsibilities and rule-based reporting; and a hybrid architecture involving the participation of advisory bodies and stakeholders. The comparison of cases indicates that none of these patterns alone guarantees favorable population outcomes, and their performance is contingent upon economic, social, welfare, and administrative conditions. "Family Protection and Youthful Population Act" has provided a set of formal rules, however, the limits of certain authorities, the linkage between coordination and budgetary, independence of evaluation, and the quality of implementing formal rules in practice require further scrutiny. this study suggests strengthening the traceability of responsibilities and resources, reporting, cross-sectoral coordination, and relatively independent evaluation as viable options to be considered in institutional design.