Marc Gasol had 17 points and seven rebounds for Memphis, while Tyreke Evans had 15 points and 12 assists. Wayne Selden and James Ennis III added 13 points each.
The Lakers ended a four-game winning streak. They were without Lonzo Ball, who injured his left knee in Saturday's overtime win at Dallas, and Brandon Ingram also didn't play because of a left ankle sprain.
Kentavious Caldwell-Pope led the Lakers with 27 points, while Kyle Kuzma finished with 18. Josh Hart had 16 points, including 10 in the fourth quarter when Los Angeles cut a 20-point lead down to single-digits in the final minutes.
The Lakers had held opponents to an average of 95.3 points over their four-game winning streak, but none of that defensive strength showed Monday. Memphis made its first five shots from outside the arc and was still shooting 60 percent from the field four minutes into the second quarter.
The Grizzlies led 60-50 going into the break.