The purpose of this study is to analyze the system of personal income taxation in Nigeria, especially with respect to its administration, equity, and effects on efficient resource usage. There have, in the past, been numerous complaints that the personal income tax in Nigeria does not yield enough revenue for the state governments, primarily because of widespread avoidance and evasion of the tax, especially by persons who do not derive income from wages and salaries. This study examines this problem in light of questions as to how the tax evolved, how important it is to state governments, how efficient and equitable it is, what administrative problems it faces, and what reforms can be implemented to best solve existing problems.