The Research objective of the discourse examined Capital Structure Substitution effect on the financial performance of various listed manufacturing firms in Nigeria.The period of study covered the timeframe of 2007 to 2021 with sample of twenty firms out of the population of fifty-nine listed manufacturing firms. This paper used earnings per share of the selected manufacturing firms to measure the financial performance .The research equally used capital structure substitution to measure the moderating effect of capital structure on financial performance. The study utilized secondary data retrieved from NSE fact book and Nigerian Exchange Group as well as yearly financial statements of the listed manufacturing firms. The research design used for the study was ex-post facto approach and the data wasanalyzed using multiple regression, descriptive statistics and co-integration test. Results revealed from the study showed that Long Term Debt to Total Equity proved a negative and significant influence on manufacturing industries financial performance. Results also showed that Long Term Debt to Market Value indicated positive as well as significant influence on industry performance, and Capital Structure Substitution has positive moderating intervening effect on financial performance. The findings of the study were statistically robust and significant. The study revealed that the independent variables proxied by Long Term Leverage Debt to Equity (LTDTE), Long Term Debt to Market Value (LTDMV) and Long Term Debt to Total Assets (LTDTA) and that Capital Structure Substitution (CSS) contributes to enhanced financial performance and capitals structure substitution has a significant (CSS) contribution to enhanced financial performance. Other findings proved that the capital structure variables affect earnings per share but on selected proxies. As a result of this, the study concluded that capital structure substitution has a significant moderating effect on financial performance of listed manufacturing firms in Nigeria. Therefore, the paper recommended that since the best optimal structure is achieved when earnings per share is maximized, firms should incorporate capital structure substitution in their business decisions. This could be achieved by encouraging listed manufacturing firms to repurchase shares, and issue debt to the level where earnings per share (EPS) will be maximized.