Papilio troilus, the spicebush swallowtail or green-clouded butterfly, is a common black swallowtail butterfly found in North America. It has two subspecies, Papilio troilus troilus and Papilio troilus ilioneus, the latter found mainly in the Florida peninsula. The spicebush swallowtail derives its name from its most common host plant, the spicebush, members of the genus Lindera.

Swallowtail butterflies are large, colorful butterflies in the family Papilionidae, and include over 550 species. Though the majority are tropical, members of the family inhabit every continent except Antarctica. The family includes the largest butterflies in the world, the birdwing butterflies of the genus Ornithoptera.