Achatina fulica is a species of large land snail that belongs in the family Achatinidae. It is also known as the African giant snail or giant African snail or giant African land snail. It shares the common name “giant African snail” with other species of snails such as Achatina achatina and Archachatina marginata.

This snail species has been considered a significant cause in pest issues around the world. Internationally, it is the most frequently occurring invasive species of snail. Outside of its native range, this snail thrives in many types of habitat in areas with mild climates. It feeds voraciously and is a vector for plant pathogens, causing severe damage to agricultural crops and native plants. It competes with native snail taxa, is a nuisance pest of urban areas, and spreads human disease.

This snail is listed as one of the top 100 invasive species in the world. The species is native to East Africa, but it has been widely introduced to other parts of the world through the pet trade, as a food resource, and by accidental introduction.

The giant African snail is native to East Africa, and can be traced back to Kenya and Tanzania. It is a highly invasive species, and colonies can be formed from a single gravid individual. In many places, release into the wild is illegal.

Nonetheless, the species has established itself in some temperate climates and its habitat now includes most regions of the humid tropics, including many Pacific islands, southern and eastern Asia, and the Caribbean. The giant snail can now be found in agricultural areas, coastland, natural forest, planted forests, riparian zones, scrub and shrublands, urban areas, and wetlands.

This species is a simultaneous hermaphrodite; each individual has both testes and ovaries and is capable of producing both sperm and ova. Instances of self-fertilization are rare, occurring only in small populations.

Although both snails in a mating pair can simultaneously transfer gametes to each other (bilateral mating), this is dependent on the size difference between the partners. Snails of similar size can reproduce in this way. Two snails of differing sizes mate unilaterally (one way), with the larger individual acting as a female, due to the comparative resource investment associated with the different genders.

Like other land snails, these have intriguing mating behaviour, including petting their heads and front parts against each other. Courtship can last up to half an hour, and the actual transfer of gametes can last for two hours. Transferred sperm can be stored within the body up to two years. The number of eggs per clutch averages around 200.

A snail may lay five to six clutches per year with a hatching viability around 90%. Adult size is reached in about six months, after which growth slows, but does not cease until death. Life expectancy is commonly five to six years in captivity, but the snails can live for up to 10 years. They are active at night and spend the day buried underground.

The giant African snail is capable of aestivating up to three years in times of extreme drought, sealing itself into its shell by secretion of a calcareous compound that dries on contact with the air.

One particularly catastrophic attempt to biologically control this species occurred on South Pacific Islands. Colonies of A. fulica were introduced as a food reserve for the American military during World War II and they escaped. A carnivorous species (Florida rosy wolfsnail, Euglandina rosea) was later introduced by the United States government, in an attempt to control A. fulica, but the rosy wolf snail instead heavily preyed upon the native Partula snails, causing the extinction of most Partula species within a decade.