The consequences of demographic changes on the national security of the Islamic Republic of Iran are influenced by important demographic factors such as fertility, mortality, and migration. These factors, which operate in the context of social, cultural, economic, and political variables, can affect the country's national security. Accordingly, the present study seeks to answer the fundamental question of what impact demographic changes have on the social security of the Islamic Republic of Iran? The information in this study was collected through a library method. Despite the fact that the relationship between population and social security is two-way and reciprocal, demographic changes have a greater impact on security issues and play a decisive role in national security by affecting cultural, social, political, and economic aspects. This research is of an applied type and is descriptive-analytical in terms of method. The statistical population of the research consisted of 17 people who were surveyed in their entirety. The results show that the geographical distribution of the population and the density pattern, the population structure and age composition, the ethnic and religious proportions in central and border cities, and external and internal migrations are among the factors that strengthen the strategic link between population and social security.