University of Sistan and Balouchestan International Journal of Business and Development Studies 2538-3302 18 1 2026 06 01 The effects of Sustainable Development Index on Economic Complexity in Oil-Exporting Countries 9806 10.22111/ijbds.2026.54501.2320 EN Mahdiyeh Rahimdel PhD student in econometrics, Faculty of Economics and Management, Urmia University, Urmia, Iran Ebrahim Ghaed Ph.D. Student Monetary- International Economics, Faculty of Economic and Administrative Sciences, Ferdowsi University of Mashhad, Mashhad, Iran Hassan Heidari Professor. Faculty of Economics and Management, Urmia University, Urmia, Iran. Journal Article 2026 01 07 The wealth of nations has been attributed to division of labor and knowledge since Adam Smith. Economists have treated the nations' and the world's economies as complex systems, but it took a decade to develop empirical studies on economic complexity with the growth of data and new models. The number of factors affecting economic complexity is large and one of these factors is sustainable development. Economic complexity is capable of representing the country's production structure. This study introduces sustainable development by fusing economic, social, and environmental factors. The research focuses on oil-exporting countries where sustainability is marked by economic development and the challenges of sustainability in the process of economic complexity, thus, it aims to assess the influence of the combined sustainable development index on economic complexity in oil-exporting countries. The paper uses 20 countries data from 1997 to 2023. The findings indicate that the sustainability index, positively and significantly relate to economic complexity. According to the results, throughout the research period in the 20 selected countries, the economic complexity index of each country rise along with an increase in its sustainability index. In other words, the rising sustainability index in these countries has the potential to facilitate economic development. Examining the Effect of Sustainable Development Index on Economic Complexity in Oil-Exporting Countries. https://ijbds.usb.ac.ir/article_9806_e39e234cb6472086742920ac05f70f42.pdf