Lemuroidea is a superfamily of primates. Members of this superfamily are called lemuroids, or lemurs. Lemuroidea is one of two superfamilies that form the suborder Strepsirrhini, itself one of two suborders in the order Primates. They are found exclusively on the island of Madagascar, primarily in forests but with some species also in savannas, shrublands, or wetlands. They range in size from the Margot Marsh's mouse lemur, at 8 cm (3 in) plus a 11 cm (4 in) tail, to the indri, at 90 cm (35 in) plus a 6 cm (2 in) tail. Lemuroids primarily eat fruit, leaves, and insects. Most lemuroids do not have population estimates, but the ones that do range from 40 mature individuals to 5,000. Most lemuroid species are at risk of extinction, with 45 species categorized as endangered, and a further 32 species categorized as critically endangered.

The 107 extant species of Lemuroidea are divided into five families. Cheirogaleidae contains 41 dwarf, mouse, and fork-marked lemur species in five genera. Daubentoniidae contains a single species, the aye-aye. Indriidae contains nineteen woolly lemur and sifaka species in three genera. Lemuridae contains 21 ruffed, ring-tailed, bamboo, and other lemur species in five genera. Lepilemuridae contains 25 sportive lemur species in a single genus.

Dozens of extinct prehistoric lemuroid species have been discovered, though due to ongoing research and discoveries the exact number and categorization is not fixed.^[1] At least 17 species and eight genera are believed to have become extinct in the 2,000 years since humans first arrived in Madagascar.^[2][3] All known extinct species were large, ranging in weight from 10 to 200 kg (22 to 441 lb). The largest known subfossil lemur was Archaeoindris fontoynonti, a giant sloth lemur, which weighed more than a modern female gorilla. The extinction of the largest lemurs is often attributed to predation by humans and possibly habitat destruction.^[2] Since all extinct lemurs were not only large (and thus ideal prey species), but also slow-moving (and thus more vulnerable to human predation), their presumably slow-reproducing and low-density populations were least likely to survive the introduction of humans.^[2] Gradual changes in climate have also been blamed, and may have played a minor role; however since the largest lemurs also survived the climatic changes from previous ice ages and only disappeared following the arrival of humans, it is unlikely that climatic change was largely responsible.^[2]

Conservation status codes listed follow the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Range maps are provided wherever possible; if a range map is not available, a description of the lemuroid's range is provided. Ranges are based on the IUCN Red List for that species unless otherwise noted.

The superfamily Lemuroidea consists of five extant families: Cheirogaleidae, Daubentoniidae, Indriidae, Lemuridae, and Lepilemuridae. Cheirogaleidae contains 41 species in five genera. Daubentoniidae contains a single species. Indriidae contains nineteen species in three genera. Lemuridae contains 21 species in five genera. Lepilemuridae contains 25 lemur species in a single genus. There are additionally three families which went extinct prior to modern record-keeping: Archaeolemuridae, Megaladapidae, and Palaeopropithecidae, as well as an extinct genus in Lemuridae.

Family Archaeolemuridae† (monkey lemurs)

• Genus Archaeolemur†: two extinct species
• Genus Hadropithecus†: one extinct species

Family Cheirogaleidae

• Genus Allocebus (hairy-eared dwarf lemur): one species
• Genus Cheirogaleus (dwarf lemurs): ten species
• Genus Microcebus (mouse lemurs): twenty-four species
• Genus Mirza (giant mouse lemurs): two species
• Genus Phaner (fork-marked lemurs): four species

Family Daubentoniidae

• Genus Daubentonia (aye-aye): one species

Family Indriidae

• Genus Avahi (woolly lemurs): nine species
• Genus Indri (indri): one species
• Genus Propithecus (sifakas): nine species

Family Lemuridae

• Genus Eulemur (true lemurs): twelve species
• Genus Hapalemur (bamboo lemurs): five species
• Genus Lemur (ring-tailed lemur): one species
• Genus Pachylemur†: two extinct species
• Genus Prolemur (greater bamboo lemur): one species
• Genus Varecia (ruffed lemurs): two species

Family Lepilemuridae

• Genus Lepilemur (sportive lemurs): twenty-five species

Family Megaladapidae† (koala lemurs)

• Genus: Megaladapis†

Family Palaeopropithecidae† (sloth lemurs)

• Genus: Archaeoindris†: one extinct species
• Genus: Babakotia†: one extinct species
• Genus: Mesopropithecus†: three extinct species
• Genus: Palaeopropithecus†: three extinct species

The following classification is based on the taxonomy described by the reference work Mammal Species of the World (2005), with augmentation by generally accepted proposals made since using molecular phylogenetic analysis, as supported by both the IUCN and the American Society of Mammalogists.^[6]

All known extinct lemurs from Madagascar are known from recent, subfossil remains.^[208] Conditions for fossilization were not ideal on the island, so little is known about ancestral lemur populations. All known extinct lemurs are thought to have died out after the arrival of humans.

• List of mammals of Madagascar
• List of primates