Kasum, Abubakar SadiqSanni, Azeezat K.Fagbemi, Temitope Olamide2020-05-232020-05-232019Kasum, A. S., Sanni, A. K. & Fagbemi, T. O. (2019): Tax Revenue Generation by Nigerian States: An Empirical Study of self-Assessment and Tax Collection Contracting System in Kwara State. Global Journal of Accounting, 5(1), 27 – 36. Published by Department of Accounting, Faculty of Management Sciences, University of Lagos, Nigeria.http://hdl.handle.net/123456789/3997Taxation as a source of revenue is very important to both the government and taxpayers. Selfassessment system requires taxpayers to compute tax liabilities and file tax returns themselves. Prior to 2011, tax collection was contracted to tax consultants and despite availability of taxable sources, states still rely heavily on federal government revenue allocation. This study investigates the effects of self-assessment tax system and tax professionals’ services on revenue generation by state governments in Nigeria. The study was a survey and data were generated through the administration of questionnaires to 80 members of staff of Kwara State Board of Internal Revenue. Both descriptive and inferential statistics were employed for analysis in the study. The analysis reveals that selfassessment system has a significant positive impact on revenue generation, while tax professionals’ services did not have positive impact on revenue generation. It was recommended that the government should improve on the implementation of the self-assessment system and embark on adequate taxpayer education and public enlightenment on tax-related matters.enSelf-Assessment,Revenue Generation,Tax ComplianceArticle