The Flyers won their second straight after losing four in a row and increased their lead in the Eastern Conference to four points over idle Washington and Pittsburgh.
A slap shot by Giroux beat James Reimer with 5:20 to go in the second, giving Philadelphia a 3-1 lead.
Boucher allowed a goal by Joffrey Lupul 7:56 into the third, but then slammed the door to post his first victory since Feb. 20.
Andrej Meszaros and Darroll Powe each scored their sixth goal of the season to give Philadelphia a 2-0 lead.
Toronto lost its third straight and has dropped five out of seven. Reimer made 30 saves for the Maple Leafs, who fell six points out of the final playoff spot in the Eastern Conference.