PurposeIn the context of the contemporary globalized environment and the rapid progression of Industry 4.0, the existing literature suggests that national intellectual capital does play a significant role in shaping diverse economic metrics. However, the connection between national intellectual capital and total factor productivity (TFP) has been largely overlooked. This paper examines the effect of national intellectual capital on productivity across 84 countries, encompassing diverse income levels, human development index (HDI) levels and continents.Design/methodology/approachThis study utilizes dynamic ordinary least squares (DOLS), fully modified ordinary least squares (FMOLS), two-stage least squares (2SLS), generalized method of moments (GMM) and pooled mean group (PMG) estimation techniques on a sample of 84 economies from 2000 to 2019.FindingsThe results reveal a significant effect of national intellectual capital on productivity. Countries with robust intellectual capital exhibit enhanced productivity and, by extension, sustainable economic growth. The findings are nuanced, illustrating varied impacts across low, middle and high-income countries and offering insights into tailored strategies for each income group. Nations with lower HDI levels derive significant benefits from investments in intellectual capital, whereas higher HDI countries experience lower returns in productivity gains from additional intellectual capital investments. Interestingly, Latin America exhibits a paradoxical negative effect of national intellectual capital on TFP.Practical implicationsThis paper makes a significant contribution to the literature by extending the discourse on intellectual capital to the national level, an area that has been relatively underexplored. The comparative analysis across income groups, human development index levels and continents enriches the understanding of the multifaceted impacts of intellectual capital on productivity. These insights are valuable for policymakers, researchers and international development agencies, providing a comprehensive perspective on how intellectual capital influences productivity in diverse economic and developmental contexts.Originality/valueTo the best of our knowledge, this is the first empirical study to investigate the impact of national intellectual capital on productivity across 84 countries, considering diverse income levels, HDI levels and continents.