Ryan Malone had two goals, Alex Killorn, Teddy Purcell, and Martin St. Louis also scored goals for the Lightning, who moved into a tie with Boston for first place in the Atlantic Division.
Jakub Voracek had two goals and Wayne Simmonds also scored for the Flyers, who were 7-1 in their previous eight games. The Flyers hadn't lost at home since Nov. 5 against Carolina.
Goaltender Steve Mason had his worst game for Philadelphia, allowing five goals for the first time in 41 games with the team since being acquired last April. He was pulled for Ray Emery after the second period.