In the United States Armed Forces, a lieutenant general is a three-star general officer in the United States Army, Marine Corps, Air Force, and Space Force.

A lieutenant general ranks above a major general and below a general. The pay grade of lieutenant general is O-9. It is equivalent to the rank of vice admiral in the other United States uniformed services which use naval ranks. It is abbreviated as LTG in the Army, LtGen in the Marine Corps, and Lt Gen in the Air Force and Space Force.

Military ranks are a system of hierarchical relationships, within an armed forces, police, intelligence agencies or other institutions organized along military lines. The military rank system defines dominance, authority, and responsibility in a military hierarchy. It incorporates the principles of exercising power and authority into the military chain of command – the succession of commanders superior to subordinates through which command is exercised. The military chain of command constructs an important component for organized collective action.Usually, uniforms denote the bearer's rank by particular insignia affixed to the uniforms. Ranking systems have been known for most of military history to be advantageous for military operations, in particular with regards to logistics, command, and coordination; as time went on and military operations became larger and more complex, military ranks increased and ranking systems themselves became more complex.

Rank is not only used to designate leadership, but to establish pay-grade as well. As rank increases, pay-grade follows, but so does amount of responsibility.Within modern armed forces, the use of ranks is almost universal. Communist states have sometimes abolished ranks (e.g., the Soviet Red Army 1918–1935, the Chinese People's Liberation Army 1965–1988, and the Albanian People's Army 1966–1991), but they had to re-establish them after encountering operational difficulties of command and control.