Population aging is a problem in recent years in developing countries such as Iran, which has posed serious concerns for the sustainability of economic growth and development. The phenomenon of population aging can be considered a change in the distribution of a country's population towards those over 65 years of age. The present study was conducted using provincial data in a descriptive-analytical method based on the econometric technique of panel data and nonlinear modeling during the period 1390 to 1402. The findings show that there is a nonlinear and inverted U-shaped relationship between the population aging ratio (the ratio of the population over 65 years of age to the total population) and the economic growth of Iranian provinces, and the maximum value of this ratio is 10.86 percent. This means that as long as the aging ratio is above 10.86 percent, increasing aging has a positive effect on the economic growth of the provinces. However, once this ratio exceeds 10.86 percent, the impact of aging on economic growth will be negative. Another finding is that the youth population ratio has a nonlinear behavior and a U-shaped curve, with the minimum value of the youth population ratio being 19.12 percent.