Ronald Lee Ermey (March 24, 1944 – April 15, 2018) was a United States Marine Corps drill instructor and actor.

Ermey often played the roles of authority figures, such as his breakout performance as Gunnery Sergeant Hartman in Full Metal Jacket, Mayor Tilman in the Alan Parker film Mississippi Burning, Bill Bowerman in Prefontaine, Sheriff Hoyt in The Texas Chainsaw Massacre remake, and plastic army men leader Sarge in the Toy Story films.

He hosted two programs on the History Channel: Mail Call, in which he answered viewers' questions about various militaria both modern and historic; and Lock N' Load with R. Lee Ermey, which focused on the development of different types of weapons.

He was a candidate for the National Rifle Association board of directors.