Conus duffyi is a species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails and their allies.
Like all species within the genus Conus, these snails are predatory and venomous. They are capable of "stinging" humans, therefore live ones should be handled carefully or not at all.
The maximum recorded shell length is 42 mm.
This species occurs in the Caribbean Sea and off the Antilles.
The average recorded depth of Conus duffyi is 2 meters.