Under color of authority is a legal phrase indicating a person is claiming or implying the acts he or she is committing are related to and legitimized by his or her role as an agent of governmental power.

The phrase can refer to lawful or unlawful acts. The statutes that define what powers police officers can exercise in the course of their duty will often state the officer must be acting "under the color of authority." On the other hand, charges of police brutality will often include the formal charge of assault "under color of authority," as they did in the Rodney King case.