Aliger gigas, originally known as Strombus gigas or more recently as Lobatus gigas, commonly known as the queen conch, is a species of large sea snail, a marine gastropod mollusc in the family of true conches, the Strombidae. This species is one of the largest molluscs native to the Caribbean Sea, and tropical northwestern Atlantic, from Bermuda to Brazil, reaching up to in shell length. "A. gigas" is closely related to the goliath conch, "Lobatus goliath", a species endemic to Brazil, as well as the rooster conch, "Lobatus gallus".