Abstract
In its ideal form, as formulated by ancient philosophers, the doctrine of separation of powers decrees that the legislature, executive and judiciary must be separate and carry out different functions in order to act as checks and balances on each other. Hence, the legislature makes laws, the executive executes the laws and the judiciary interprets the laws. Against this background, this paper subjected the extant Constitution of the Federal Republic of Nigeria, 1999 as amended to rigorous scrutiny in order to determine the extent of its compliance with the concept of separation of powers. Deploying the doctrinal research method, the paper exhaustively examined relevant textual constitutional provisions on separation of powers and judicial interpretations placed on them. The paper found that although separation of powers is observed because distinct functions are reserved for each of the three arms of government, yet there are many areas of intermingled powers and shared competences between these three arms of government such as in the appointment of Heads of Court which is made by the executive subject to confirmation by the legislature or exercise of quasi-judicial powers by the legislature during legislative oversight. In order to maintain this unique model of power sharing without compromising separation of powers, it was recommended among other things that each arm of government must not exceed its allowed limit of shared competences failing which the judiciary should do the needful.
Keywords: Executive, Judiciary, Legislature, Oversight, Separation Of Powers