This study delved into the connection between Nigerian manufacturing enterprises' financial performance and relational capital investment. The investigation was conducted using the ex post facto research design. The populace of the study consist of 30 manufacturing companies cutting across several subsectors, including consumer goods, healthcare, oil and gas, industrial goods, natural resources, and conglomerates that have actively traded spanning from 2010 and 2019. The multiple regression model was employed to test the formulated hypotheses. The study observed that return on assets and relational capital investment of manufacturing companies were positively and significantly correlated. However, the return on equity and earnings per share of Nigerian manufacturing enterprises were positively and insignificantly correlated with relational capital investment. The study concluded that human capital investment, structural capital investment and relational capital investment make the most contribution to the financial performance of manufacturing companies in Nigeria. It is recommended that manufacturing businesses should invest more in human capital to maximize the already existing positive effect on financial performance. Also, manufacturing companies are advised to improve investment in relational capital to maximize returns