De Facto, in law, phrase used to signify the exercise of a power in spite of the absence of legal authority. De facto contrasts with de jure, which indicates the lawful exercise of a power. The phrase is applied when a person or group occupies public office or purports to exercise political or other authority without legal right.

In constitutional and international law, de facto means a power exercised but without established legal basis. It can be applied to a revolutionary government, such as the Continental Congress, which had no legal basis but which showed that its authority was effective by its victorious conduct of the American War of Independence. Success in the war resulted in recognition of the independence of the 13 colonies and in de jure recognition of the Continental Congress by Great Britain and other countries. For various reasons, if a country wishes to enter into relations with a government, revolutionary or otherwise, but is unwilling to accord de jure recognition, it will generally accord de facto recognition.

In business law, a de facto corporation is one that is functioning and in pursuance of an effort made in good faith to organize a corporation within existing law. If a de facto corporation that has exercised corporate powers for a considerable period of time inadvertently omits a requirement for establishing a regular corporation, most courts hold that the corporation is entitled to practically the same rights and protection as a regularly constituted, or de jure, corporation.

Similarly, courts will, in certain cases, examine the decisions of public bodies even when their powers are de facto and have no formal legal basis.