Boston won its sixth straight, all of those games played since the Celtics lost Rajon Rondo with a torn knee ligament.
The Celtics put the game away with a 37-point third period and took a 26-point lead into the final quarter.
Dwight Howard returned to the Los Angeles lineup after his shoulder problems caused him to miss three consecutive games. Howard, however, fouled out in the fourth quarter and produced just nine points.
Kobe Bryant led the Lakers with 27 points. Los Angeles is 3-2 on a seven-game road trip that has stops remaining in Charlotte and Miami.