The James Norris Memorial Trophy, or simply the Norris Trophy, is awarded annually to the National Hockey League's top "defense player who demonstrates throughout the season the greatest all-round ability in the position". It is named after James E. Norris, the longtime owner of the Detroit Red Wings. The James Norris Memorial Trophy has been awarded 62 times to 26 players since its beginnings in 1953–54. At the end of each season, members of the Professional Hockey Writers' Association vote to determine the player who was the best defenseman during the regular season.

Defence or defense in ice hockey is a player position that is primarily responsible for preventing the opposing team from scoring. They are often referred to as defencemen, D, D-men or blueliners. They were once called cover-point.