Per Kayode Eso, JSC, in the case of Stitch v. Attorney General of the Federation, Administrative Law is the law that relates to the discharge of functions of a public nature in government and administration. Administrative law is also considered the body of law that governs the activities of administrative agencies of government. Per Ivor Jennings, Administrative law is the law determining the organization, powers, and duties of administrative authorities.

There are several definitions of administrative law from different jurisdictions. Indeed, from its Common law origin in England, administrative law has been defined differently by different authors and academic writers. The Kernel of the whole subject of Administrative Law, per DCM Yardley, is the control of power within its lawful compass. According to Stott and Felix, it is the law that regulates the exercise of power conferred under the law upon governmental bodies. According to Bradley and Ewing, it is a branch of public law concerned with the composition, procedures, powers, duties, rights and liabilities of various organs of government. According to Peter Leyland and Terry Woods, it is regarded as the area of Law concerned with the control of governmental Powers which originate in primary legislation or in the prerogative. Thus, from the above definitions, Administrative law is considered a branch of public law which deals with the decision-making of administrative units of government.