Ninety-one countries fall into three developing nations categories: Least developed countries (LDCs), landlocked developing countries (LLDCs), and small island developing states (SIDS). These 91 nations have largely been left out of studies on the economic impact of fixed and mobile broadband. Economic Impact of Broadband in LDCs, LLDCs, and SIDS (An Empirical Study) fixes that. This empirical study delves deep into how broadband investment can lead to higher economic returns in these countries. Authors use cross-sectional time-series analysis to study the subject in these 91 nation-states from 2000 to 2017 and confirm that there is a positive economic impact from investing in fixed and mobile broadband in these countries. It measures the direct and indirect impact in several economic sectors including agriculture, education, financial services, government, health, and disaster management, of that investment.