Allied Command Operations (ACO) is one of The North Atlantic Treaty Organisation's (NATO) two strategic military commands. The other command being Allied Command Transformation (ACT) in Norfolk, Virginia.

ACO is commanded by the Supreme Allied Commander Europe (SACEUR) and is responsible for all Alliance military operations. The command headquarters, known as Supreme Headquarters Allied Powers Europe, or SHAPE, is located in Casteau near Mons, Belgium. The mission of ACO and the SACEUR is to contribute to preserving the peace, security and territorial integrity of NATO member nations in its area of responsibility.