The aim is to investigate the threshold effects of investment on the relationship between telecommunication infrastructure and economic growth, and the Panel Staggered Regression (PSTR) model was used based on annual data from selected developing countries during the period 2000-2023. The results of the estimation of the nonlinear part of the model in the group of developing countries indicate a significant positive relationship between the study variables except the inflation rate variable and the economic growth index. According to the results, a one-unit increase in the composite index of telecommunication infrastructure, employment of educated labor, gross capital formation, foreign direct investment, urbanization rate, and degree of economic freedom leads to an increase of 0.25, 0.11, 0.25, 0.16, 0.03, and 0.04 units in the economic growth index, respectively. Also, a one-unit increase in the inflation rate leads to a decrease of 0.14 units in the economic growth index. Today's competitive world relies more on the development of new telecommunication infrastructure than on the availability of resources. Therefore, manufacturing firms continue to survive based on continuous modernization of their products and technologies. Countries will have an important position at the international level by investing in education, research and development. The openness of the global economy leads to an increase in the rate of university education and appropriate specialization for development, making it possible to confront and compete with other countries. It is suggested that governments and economic policymakers help benefit the domestic economy of the countries under study by providing platforms for the use of telecommunications and Internet infrastructure, including reducing access costs and improving Internet speed.