The inadequacies in Nigeria's traditional tax administration system have posed significant challenges to tax revenue generation, including inefficiencies, corruption, and lack of transparency, ultimately resulting in low tax revenue generation. This study was therefore conducted to examine the effect of E-tax system on tax compliance cum revenue generation in Nigeria. The study was anchored on three electronic tax system variables, namely e-filing of tax returns, online TIN registration, online tax clearance certificate processing,. The study adopted a survey research design, while data were obtained through questionnaires administered to selected personnel of the Federal Inland Revenue Service now known as the Nigerian Revenue Service and relevant tax practitioners. Out of one hundred and fifty (150) questionnaires administered, one hundred and forty-four (144) respondents correctly completed and returned for analysis. Descriptive statistics, model summary, analysis of variance and multiple regression analysis were employed for analysis with the aid of SPSS. The findings revealed that e-filing of returns and online TIN registration had positive but non-significant relationships with tax revenue generation, while online tax clearance certificate processing, had positive and significant relationships with tax revenue generation in Nigeria. The study concluded that E-tax system jointly enhance tax compliance and tax revenue generation in Nigeria. It was recommended that the Nigerian Revenue Service should strengthen digital tax platforms, improve user support and awareness, expand secure e-payment channels, automate VAT and PAYE return processing and simplify electronic personal assessment systems in order to improve voluntary compliance and revenue collection.