Papilio elwesi is a butterfly of the family Papilionidae. The species is endemic to China and Vietnam.
Papilio elwesi (along with P. maraho) differs from all other Papilio species in the tail of the hindwing being so dilated that two veins are necessary to support it. Together these two species form the subgenus Agehana.
The larvae feed on Lauraceae species.
It is named for British botanist, entomologist, author, lepidopterist, collector and traveller, Henry John Elwes.