American Journal of Business Management, Economics and Banking ISSN (E): 2832-8078 Volume 16, | Sep., 2023 Page | 117 www.americanjournal.org STRUCTURAL CAPITAL AND FINANCIAL PERFORMANCE OF QUOTED MANUFACTURING FIRMS IN NIGERIA Doghudje, Ufuoma Sylvia Department of Accounting, Faculty of Management Sciences, University of Port Harcourt. Fumsky002@yahoo.co.uk Ogbonna, Gabriel N. Professor, Department of Accounting, Faculty of Management Sciences, University Of Port Harcourt. Ibanichuka, Emmanuel A. L. Professor, Department of Accounting, Faculty of Management Sciences, University Of Port Harcourt A B S T R A C T K E Y W O R D S This study examined the relationship between structural capital investment and the financial performance of quoted manufacturing firms in Nigeria, with specific attention to Return on Assets of manufacturing firms. Utilizing an ex-post facto research design, this study employed secondary data extracted from the annual reports of 30 publicly quoted manufacturing companies in Nigeria. A total of 300 observations were analyzed using panel data regression models. The results revealed a statistically significant positive relationship between structural capital investment and ROA, suggesting that investment in organizational structure, systems, and processes could contribute to efficient asset utilization. Conversely, a non-significant relationship was observed between structural capital investment and EPS, raising questions about the immediate impact of such investments on shareholder value in the Nigerian manufacturing sector. The study recommends that manufacturing companies should strategically invest in structural capital such as organizational culture, information systems, and processes, with a focus on long-term asset optimization, given its positive relationship with ROA. Structural Capital, Financial Performance, Return on Assets, Intellectual capital, Manufacturing Firms. Introduction In the 21st century, the role of intangible assets in determining the financial performance of firms has received considerable attention, largely eclipsing the focus on traditional, tangible assets. The global economy is increasingly knowledge-based, where intangible assets such as human capital, relational