The Bailey-Matthews National Shell Museum & Aquarium is a museum and aquarium devoted to seashells, conchology, and malacology, including the paleontological and archeological/anthropological aspects of the study of shells. The museum is located in the city of Sanibel, Florida on the Gulf of Mexico coast of Southwest Florida.

The Bailey-Matthews National Shell Museum opened to the public in 1995, and operates as an information and reference center for national and international scientists, students, and shell enthusiasts, particularly those who are interested in the marine, terrestrial, and freshwater mollusks of the Gulf of Mexico and Florida. The Museum, which is a facility of the Shell Museum and Educational Foundation, Inc., received its first accreditation from the American Alliance of Museums in March 2010.

It was heavily damaged by Hurricane Ian and the museum reopened in February 2023.

The museum's exhibits include shells from all over the world. However, many shells on show in the museum are from Florida, and a substantial number are from Sanibel and Captiva islands. This is because Sanibel Island is considered one of the best seashell collecting spots in the world (comparable to Jeffreys Bay in Africa and the Sulu Archipelago in the Pacific). The museum also owns a collection of Pacific Ocean cowries and cones donated by actor Raymond Burr, who owned an island in the Fijis, and who led the efforts to raise funds to build the museum.

Permanent exhibits include Living Gallery of Aquariums and Marine Life and the Great Hall of Shells. In addition, there are changing special exhibitions throughout the year.

The Great Hall of Shells is the historic heart of the Museum, with extensive permanent exhibits of shells in an octagonal gallery space with 30-foot ceilings. Following significant damage from Hurricane Ian in 2022, the Museum embarked on a full re-design and re-installation of the shell exhibits and the Great Hall. The Great Hall of Shells partially reopened in May of 2025, featuring specimens from all over the world that are highlights selected from the Museum’s collection of nearly 600,000 shells. Themes of these exhibits include global biodiversity, shapes and colors, and time and evolution; and special focuses on groups including cones, cowries, volutes, murexes, scallops, and carrier shells.

The second phase, located in the periphery of the Hall, reopened in October of 2025. This final phase includes exhibits on Southwest Florida Shells, World Record Shells, Florida Land Snails, Florida Fossil Shells, shells in human History and Culture, use of shells by the Calusa people, and Conservation and Environmental Issues as they relate to mollusks. The completion of this phase marks the end of the Museum’s rebuilding following Hurricane Ian in 2022.

The Living Gallery of Aquariums and Marine Life exhibits approximately 60 species of mollusks and other animals including the giant pacific octopus, two-spot octopus, giant clam, queen conch, flamingo tongue, giant triton, dozens of mollusks common to Southwest Florida, cold water species found in the Pacific Northwest, and corals and fish from around the world.