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.

Queen conch (Strombus gigas) is a species of large marine snail that is found in tropical waters of the West Indies, the Caribbean, and Florida Keys. It is an important fishery resource and is also found in the Gulf of Mexico. The species is most commonly found in shallow seagrass beds, where it feeds on algae and other small organisms.

The queen conch, Strombus gigas, is the largest molluscan gastropod (shell length, SL, of 7 to 9 inches; 18 to 23 cm) of the six conch species found in the shallow sea-grass beds of Florida, the Bahamas, Bermuda, the Caribbean Islands, and the north-ern coasts of Central and South America.