The study examined the effect of Treasury Single Account (TSA) on tax revenue collected in Nigeria. Company income tax, value added tax, and petroleum profit tax formed the dependent variables of the study. The study adopted an ex-post-facto research design, covering the period between 2011 and 2019. Secondary data were extracted from the Federal Inland Revenue Service website. Paired Sample T-test technique was used for the data analysis. In line with the specific objectives of the study which was to ascertain the effect treasury single account implementation on company income tax, value added tax, and petroleum profit tax revenue collected in Nigeria, it was revealed that TSA has a positive and significant effect on company income tax and value added tax revenue collected in Nigeria. TSA has a negative and insignificant effect on petroleum profit tax in Nigeria. This implies that TSA implementation has increased company income tax and value added tax collected in Nigeria. It is recommended therefore that the continuous use of TSA should be guaranteed by the government. This is because it led to an increase in company income tax collection in Nigeria. Every factor that works against its continued existence should be subdued. They should ensure that tax authorities continue to comply with TSA rules in remittance of value added tax collected to the consolidated revenue fund. They should ensure that Nigerian National Petroleum Corporation (NNPC) and other oil and gas regulating authorities comply fully to the dictates of TSA.