This paper investigates the connection between human resource accounting (HRA) and profitability of listed deposit money banks (DMBs) in Nigeria for period, 2010-2020. While controlling for size effect, this aims to determine the effect of salaries and wages, directors’ remuneration, and retirement benefits and costs, on banks’ profitability (proxy by Return on Asset (ROA)). Secondary data sourced from published annual financial statements of nine purposefully selected DMBs quoted on the Nigerian Exchange Group, were analyzed using Panel Autoregressive Distributed Lag (P-ARDL) model and panel Granger causality technique. This study reveals that retirement benefits and costs, and directors’ emolument exert positive and significant effect on ROA while salary and wages has positive but non-significant effect on ROA. Furthermore, there is a unidirectional causality flow from ROA to salaries and wages and banks size. It is therefore concluded that investment in human resources have positive and significant effect on the profitability of banks in Nigeria and banks profitability dictates their wage-paying ability and size. It is recommended that banks should investment more in their HR particularly by providing a much more guaranteed retirement benefits to their employees and also handsomely rewarding their currently serving directors and employees.