Using a dataset that includes 24 developing and developed countries for the period 1984–2017, this research adopts outstanding deposits with commercial banks to GDP ratio and research and development (R&D) expenditure to GDP ratio as main proxies of financial inclusion and R&D, respectively. The empirical results suggest that promoting financial inclusion or R&D can offset the harmful effects of uncertainty on economic performance and that the impact of R&D with uncertainty is statistically significantly greater than the impact of financial inclusion with uncertainty. Moreover, our subsample analyses indicate that the mitigating effects of financial inclusion and R&D exist in nonfinancial crisis periods, developed countries, and the European region. To address endogeneity concerns, we employ six instrumental variables in a two-stage least squares regression (IV-2SLS). Our findings have useful policy implications to government for dealing with economic policy uncertainty for the economy’s benefit.