The growing investment in new information technologies has greatly promoted the digitalization of tax administration across the world. However, over the years, developing countries such as Nigeria have been confronted with the challenges of mobilization of tax revenue due to primitive manual tax administration systems resulting in tax evasion, corruption, leakages, and tax fraud. This study, therefore, investigated the impact of digitalization of tax administration on the performance of Kwara State Internal Revenue Service (KW-IRS). The specific objectives of this study were to: (i) examine the extent to which e-tax registration influences the performance of KW-IRS), and (ii) determine the impact e-tax payment on the performance of KW-IRS. This study employed a quantitative cross-sectional survey research design and used a random sampling technique to select 292 respondents from both the demand and supply sides. The study employed PLS-SEM technique for quantitative data analysis. Findings revealed that: (i) e-tax registration has significant positive influence on revenue performance (β= 0.198, = 0.660, p= < 0.05, (ii) e-tax payment has significant positive impact on revenue performance (β = 0.249, t = 2.655, p = < 0.05) implying that e-tax registration and e-tax payment have significantly improved revenue performance. Based on findings, this study, therefore, recommended that KW-IRS should further scale up the use of digital tools in all tax streams as well as a robust electronic tax audit to track the payment pattern of taxpayers.