Administrative law is a branch of law that governs the activities of executive branch agencies of government. It encompasses laws and legal principles governing the administration and regulation of government agencies (both federal and state) . Administrative law includes executive branch rule making, adjudication, and the enforcement of laws. Administrative law deals with the decision-making of such administrative units of government that are part of the executive branch in areas such as international trade, manufacturing, the environment, taxation, broadcasting, immigration, and transport.

Key features of administrative law include the organization, powers, duties, and functions of public authorities of all kinds engaged in administration; their relations with one another and with citizens and nongovernmental bodies; legal methods of controlling public administration; and the rights and liabilities of officials. Administrative law is complemented by constitutional law, and the line between them is hard to draw. The term "administrative law" encompasses the procedures under which agencies operate, as well as external constraints upon them (such as the Administrative Procedure Act, constitutional limitations, and judicial review) .

Administrative law research can be complex due to the multiple functions of federal agencies. It involves a broad spectrum of materials, from proposed regulations to presidential orders to the opinions of administrative law judges. Understanding administrative law is important because it has a big impact on the everyday lives of citizens.