The Security Service of Ukraine is the main internal security agency of the Ukrainian government. Its main duties include counter-intelligence activity and combating organized crime and terrorism. The Constitution of Ukraine defines the SBU as a military formation, and its staff are considered military personnel with ranks. It is subordinated directly under the authority of the president of Ukraine. The SBU also operates its own special forces unit, the Alpha Group.

A security agency is a governmental organization that conducts intelligence activities for the internal security of a nation. They are the domestic cousins of foreign intelligence agencies, and typically conduct counterintelligence to thwart other countries' foreign intelligence efforts.