The 26-year-old defenseman could have become a restricted free agent at the end of the season.
"He deserves every little bit of it," Los Angeles coach Todd McLellan said after a 3-1 win against the Vegas Golden Knights on Sunday. "We have a ton of confidence in him. I think he feels comfortable here with the group, and he'll have a chance to get even more comfortable. With the reward comes more responsibility. That's part of the League, and we will expect more from him."
Roy has seven assists and is averaging 19:32 of ice time in 25 games this season. He is third among Kings defensemen in ice time, behind Drew Doughty (26:29) and Mikey Anderson (21:11).
Roy has scored 31 points (six goals, 25 assists) in 120 games after being selected by Los Angeles in the seventh round (No. 194) of the 2015 NHL Draft.
The Kings (13-11-6) are in fifth place in the eight-team Honda West Division. The top four teams will make the Stanley Cup Playoffs. They play at the San Jose Sharks on Monday to begin a four-game road trip.
NHL.com independent correspondent Dan Greenspan contributed to this report
