The implementation of Treasury Single Account (TSA) in Nigeria ushered in some drastic changes such that Central Bank of Nigeria (CBN) takes over the custodian of public fund and Deposit Money Banks (DMBs) serve as collecting agent throughout the federation. This seems to be affecting the liquidity state of DMBs. A bank with high liquidity problem might not be able to withstand negative shocks and contribute to the stability of the financial system. An in-depth analysis of the impact of TSA on the profitability of Money Deposit banks will not only clarify the disaggregated findings reported by previous studies, but also provide suggestions on how DMBs could improve their liquidity state. Based on incremental and stakeholders' theory, this research examines the impact of Treasury Single Account (TSA) on the Profitability of Deposit Money Banks (DMBs) in Nigeria. Out of all the listed Deposit Money Banks (DMBs) in Nigeria, purposive sampling technique was used to select all the 6 Systematically Important Banks (SIB) and data were collected on four indicators of profitability of banks such as Earning per Share (EPS), Profit after Tax (PAT), Return on Equity (ROE) and Return on Assets for the period of 6 years divided into Pre-TSA (2012-2014) and Post-TSA (2015-2017). It was discovered that through the analysis carried out via paired sampled t-test that TSA exerts a positive insignificant impact on all the indicators of profitability covered by this study except Profit after Tax (PAT) that has a negative insignificant impact. Finally, it was recommended that managers of DMBs should work out modalities that will foster the embracement of the core values of the banking system to collect depositors' funds, keep them safe and engage in intermediation to create wealth and jobs for the economy. Consequently, overdependence on government fund for operational activities should be discouraged.