Brigadier general is a rank in the army. He is normally in command of a brigade, about 3,000 men. It is between the rank of major general and colonel. In the United States, brigadier general is also a rank in the Air Force and Marines and is also called O-7. Brigadier in the British Army is OF-6, and also in NATO. The difference is that NATO classes both first and second lieutenants as OF-1.