Abstract
The principle of legality represents one of the most important principles of the state of law, which significantly contributes to defending the law order and the social balance. Established as a principle of the organization and functioning of the state public authorities at the Revolution of 1789 in France, the acknowledgement of the principle of legality in an act having a constitutional value marked the moment of foundation for the state based on law principles and represented a premise of creating a modern public administration. The principle is present at the level of each judiciary branch, which provides for its popularity due to its specificity. The paper aims at achieving a brief analysis of the role of the principle of legality in public law, presenting its importance in constitutional and administrative law.