Donald Arvid Nelson (born May 15, 1940 in Muskegon, Michigan) is a National Basketball Association head coach. He was named the head coach of the Golden State Warriors on August 30, 2006, his second stint with the franchise. He has also coached the Milwaukee Bucks, the New York Knicks and the Dallas Mavericks. Don Nelson's overall NBA coaching record is 1,232-920 heading into the 2007-08 NBA season.

An innovator, Nelson is credited with, among other things, inventing the concept of the point forward, a tactic which is frequently employed by teams at every level today. His unique brand of basketball is often referred to as Nellie Ball.