The study examines the effect of agency cost on shareholders’ return on capital in Nigeria by drawing samples from non-finance firms that are listed on the floor of the Nigerian Exchange Group (NGX) from 2012-2022. In this study, we ensure the use of agency cost proxies such as asset tangibility, managerial ownership, and director’s remuneration while shareholders return on capital is measured in terms of return on equity. Specifically, to achieve the objective of the study, we conducted a pool least square regression before proceeding to check for inconsistencies with the basic assumptions of the OLS regression. Succinctly, these diagnostics tests include test for multicollinearity as well as test for heteroscedasticity. This study is based on an expo-facto research design. The study covers a period of ten (10) years. That is, from 2012 to 2021 employing non-finance firms listed on the floor of the Nigerian Exchange Group. The population for this study consist of all the listed non-finance firms on the Nigeria Exchange Group. As of 31st December 2021, the total number of listed non-finance firms was 109. The sample size was arrived at through a purposive sampling technique. This is because the firms were included in the sample if they meet certain criteria to enable homogenous sample. These criteria are that the firms must be listed at the stock exchange before the study period (2012); the firms must remain listed during the study period and not be delisted before the end of the study period (2021). This will be done to ensure a balanced panel data structure through the use of a homogeneous periodic scope, which is required for the estimate procedure. From the foregoing, the final sample size of this study consist of 73 listed non-finance firms in Nigeria. Particularly, we conclude that asset tangibility and managerial ownership significantly reduces shareholder’s return on capital. However, we also conclude that directors’ remuneration insignificantly reduces shareholder’s return on capital. Hence, we recommend that although a high ratio of fixed to total assets provides creditors with a high level of security since they will be able to liquidate more assets in case bankruptcy, management of non-finance firms should endeavour to keep the ratio low so as to reduce agency cost and increase shareholder’s return on capital. Furthermore, we recommend that managerial ownership should be reduced to mitigate agent principal conflict and thus improve shareholder’s return on capital.