A nelson hold is a grappling hold which is executed by one person from behind the opponent, generally when both are on the mat face down with the opponent under the aggressor. One or both arms are used to encircle the opponent's arm under the armpit, and secured at the opponent's neck. Several different nelson holds exist, and they can be separated according to the positioning of the encircling arm(s). A nelson is used to control an opponent or to turn them over onto their back and execute a pin.

The term "nelson" is derived from "full nelson", which dates back to the early 19th century. It has been suggested that it was named after Horatio Nelson, who used strategies based on surrounding the opponent to win the Battle of the Nile and the Battle of Trafalgar; it was also suggested that Bobby Nelson was the innovator and/or the name inspiration of the Nelson hold.