Jeff Carter and Justin Williams scored in the second for the Kings, who won their third straight and 11th in 14 games while remaining in third place in the Pacific Division.
Matt Read and Jakub Voracek had Philadelphia's goals. The Flyers had won five in a row. They dropped to 12-3-1 in their last 16 games.
Los Angeles had a 2-0 lead entering the final period, but Philadelphia tied it at 2 before King's winning score with 9:24 remaining.
The play started with a Flyers turnover just outside their zone. Slava Voynov raced down the right side, creating a 2-on-1 with King. King took Voynov's perfectly placed cross-ice pass and beat Ray Emery high on the stick side on a forehand from close range.
Carter opened the scoring 1:49 into the second period with a wrister from the left circle. Alec Martinez took the initial shot from the point, and it deflected off the skate of defenseman Mark Streit and right to Carter.
It looked as if Vincent Lecavalier had tied it a minute later, but his shot to a wide-open net went off the right post, then the crossbar and finally the left post. The goal light went on and the arena horn blared signaling a goal, but officials never stopped play. The officials' no-goal ruling was later upheld by replay.
Williams then scored with 2:31 remaining in the period when he finished a backhander after Emery gave up a bad rebound. Robyn Regehr took a wrist shot from the point that bounded off Emery's pads to Williams, who lifted it into the empty net.
The Kings also had a goal disallowed in the period when Martinez's apparent tally was waved off because Carter cross-checked Kimmo Timonen in front of Emery just prior to Martinez's shot.
Los Angeles dominated the period, outshooting Philadelphia 20-9.
Philadelphia pulled within a goal just 29 seconds into the third period when Read was credited for a score when the puck deflected off the skate of defenseman Jake Muzzin.
Voracek provided the equalizer with 11:42 remaining in the third period when he deflected home Scott Hartnell's shot from the point after the Kings turned it over in their zone.
Emery started in place of Steve Mason. It was just the third start and fourth appearance for Emery in the last 18 games. Emery was sidelined for five of those games with a lower body injury suffered Feb. 27 against San Jose.
Mason was 4-0 with a 1.50 goals-against average during the winning streak, but Emery has had success in his career against Los Angeles and entered 2-0-1 with a 1.34 GAA against the Kings.
Emery played well in the scoreless first period when he made 14 saves, including a pair of point-blank attempts by Kyle Clifford and Jarret Stoll. He finished with 38 saves.
Jonathan Quick made 30 saves for Los Angeles.
Carter and Mike Richards, both former Flyers, were booed every time they touched the puck in the first period. The duo, who helped the Kings win the Stanley Cup in 2012, were traded after the 2011 season. Carter was playing against his former club in Philadelphia for the first time. Williams also is a former Flyer.
NOTES: The teams split the regular-season series, with Philadelphia winning 2-0 at Los Angeles on Feb. 1. . Kings coach Darryl Sutter coached Flyers counterpart Craig Berube when Sutter led Calgary. . Philadelphia RW Steve Downie didn't dress after suffering an upper-body injury in Saturday's 4-1 win over St. Louis. Tye McGinn was recalled from Adirondack of the AHL. ... Kings captain Dustin Brown didn't show any ill effects of a chest injury that forced him to leave Saturday's 4-0 win at Florida. . Los Angeles improved to 24-1 when leading after the second period.