The Commandant General Royal Marines is the professional head of the Royal Marines. The title has existed since 1943. The role is held by a General who is assisted by a Deputy Commandant General, with the rank of brigadier. This position is not to be confused with Captain General Royal Marines, the ceremonial head. The Commandant General Royal Marines is the counterpart to the Commandant of the United States Marine Corps.

Captain General Royal Marines is the ceremonial head of the Royal Marines. The current Captain General is King Charles III. This position is distinct from that of the Commandant General Royal Marines, the professional head of the corps, who is currently ranked as a General.