This is a list of the mammal species recorded in Nicaragua. Of the mammal species in Nicaragua, two are endangered, four are vulnerable, and four are near threatened. One species has been classified as extinct.

The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature:

Some species were assessed using an earlier set of criteria. Species assessed using this system have the following instead of near threatened and least concern categories:

Subclass: Theria

Infraclass: Metatheria

Order: Didelphimorphia (common opossums)

Didelphimorphia is the order of common opossums of the Western Hemisphere. Opossums probably diverged from the basic South American marsupials in the late Cretaceous or early Paleocene. They are small to medium-sized marsupials, about the size of a large house cat, with a long snout and prehensile tail.

Family: Didelphidae (American opossums)
Subfamily: Caluromyinae
Genus: Caluromys
 Derby's woolly opossum, Caluromys derbianus VU
Subfamily: Didelphinae
Genus: Chironectes
 Water opossum, Chironectes minimus LR/nt
Genus: Didelphis
 Common opossum, Didelphis marsupialis LR/lc
 Virginia opossum, Didelphis virginiana LR/lc
Genus: Marmosa
 Alston's mouse opossum, Marmosa alstoni LR/nt
 Mexican mouse opossum, Marmosa mexicana LR/lc
Genus: Metachirus
 Brown four-eyed opossum, Metachirus nudicaudatus LR/lc
Genus: Philander
 Gray four-eyed opossum, Philander opossum LR/lc

Infraclass: Eutheria

Order: Sirenia (manatees and dugongs)

Sirenia is an order of fully aquatic, herbivorous mammals that inhabit rivers, estuaries, coastal marine waters, swamps, and marine wetlands. All four species are endangered.

Family: Trichechidae
Genus: Trichechus
 West Indian manatee, T. manatus

Order: Cingulata (armadillos)

The armadillos are small mammals with a bony armored shell. They are native to the Americas. There are around 20 extant species.

Family: Dasypodidae (armadillos)
Subfamily: Dasypodinae
Genus: Dasypus
 Nine-banded armadillo, Dasypus novemcinctus LC
Subfamily: Tolypeutinae
Genus: Cabassous
 Northern naked-tailed armadillo, Cabassous centralis DD

Order: Pilosa (anteaters, sloths and tamanduas)

The order Pilosa is extant only in the Americas and includes the anteaters, sloths, and tamanduas.

Suborder: Folivora
Family: Bradypodidae (three-toed sloths)
Genus: Bradypus
 Brown-throated three-toed sloth, Bradypus variegatus LC
Family: Choloepodidae (two-toed sloths)
Genus: Choloepus
 Hoffmann's two-toed sloth, Choloepus hoffmanni LC
Suborder: Vermilingua
Family: Cyclopedidae
Genus: Cyclopes
 Silky anteater, C. didactylus LC
Central American silky anteater, C. dorsalis 
Family: Myrmecophagidae (American anteaters)
Genus: Myrmecophaga
 Giant anteater, Myrmecophaga tridactyla VU
Genus: Tamandua
 Northern tamandua, Tamandua mexicana LC

Order: Primates

The order Primates contains humans and their closest relatives: lemurs, lorisoids, tarsiers, monkeys, and apes.

Suborder: Haplorhini
Infraorder: Simiiformes
Parvorder: Platyrrhini (New World monkeys)
Family: Cebidae
Subfamily: Cebinae
Genus: Cebus
 Panamanian white-faced capuchin, Cebus capucinus LC
Family: Atelidae
Subfamily: Alouattinae
Genus: Alouatta
 Mantled howler, Alouatta palliata LC
Subfamily: Atelinae
Genus: Ateles
 Geoffroy's spider monkey, Ateles geoffroyi LC

Order: Rodentia (rodents)

Rodents make up the largest order of mammals, with over 40% of mammalian species. They have two incisors in the upper and lower jaw which grow continually and must be kept short by gnawing. Most rodents are small though the capybara can weigh up to.

Suborder: Hystricognathi
Family: Erethizontidae (New World porcupines)
Subfamily: Erethizontinae
Genus: Coendou
 Mexican hairy dwarf porcupine, Coendou mexicanus LR/lc
Family: Dasyproctidae (agoutis and pacas)
Genus: Dasyprocta
 Central American agouti, Dasyprocta punctata LR/lc
Family: Cuniculidae
Genus: Cuniculus
 Lowland paca, Cuniculus paca LC
Family: Echimyidae
Subfamily: Eumysopinae
Genus: Hoplomys
 Armored rat, Hoplomys gymnurus LR/lc
Genus: Proechimys
 Tome's spiny-rat, Proechimys semispinosus LR/lc
Suborder: Sciurognathi
Family: Sciuridae (squirrels)
Subfamily: Sciurinae
Tribe: Sciurini
Genus: Microsciurus
 Central American dwarf squirrel, Microsciurus alfari LR/lc
Genus: Sciurus
 Deppe's squirrel, Sciurus deppei LR/lc
 Richmond's squirrel, Sciurus richmondi LR/nt
 Variegated squirrel, Sciurus variegatoides LR/lc
Family: Geomyidae
Genus: Orthogeomys
 Nicaraguan pocket gopher, Orthogeomys matagalpae LR/lc
Family: Heteromyidae
Subfamily: Heteromyinae
Genus: Heteromys
 Desmarest's spiny pocket mouse, Heteromys desmarestianus LR/lc
 Salvin's spiny pocket mouse, Heteromys salvini LR/lc
Family: Cricetidae
Subfamily: Tylomyinae
Genus: Nyctomys
 Sumichrast's vesper rat, Nyctomys sumichrasti LR/lc
Genus: Ototylomys
 Big-eared climbing rat, Ototylomys phyllotis LR/lc
Genus: Tylomys
 Peters's climbing rat, Tylomys nudicaudus LR/lc
Subfamily: Neotominae
Genus: Baiomys
 Southern pygmy mouse, Baiomys musculus LR/lc
Genus: Neotoma
 Nicaraguan woodrat, Neotoma chrysomelas LR/lc
Genus: Peromyscus
 Naked-eared deer mouse, Peromyscus gymnotis LR/lc
 Mexican deer mouse, Peromyscus mexicanus LR/lc
 Stirton's deer mouse, Peromyscus stirtoni LR/lc
Genus: Reithrodontomys
 Short-nosed harvest mouse, Reithrodontomys brevirostris LR/lc
 Fulvous harvest mouse, Reithrodontomys fulvescens LR/lc
 Slender harvest mouse, Reithrodontomys gracilis LR/lc
 Mexican harvest mouse, Reithrodontomys mexicanus LR/lc
 Nicaraguan harvest mouse, Reithrodontomys paradoxus LR/nt
 Sumichrast's harvest mouse, Reithrodontomys sumichrasti LR/lc
Genus: Scotinomys
 Alston's brown mouse, Scotinomys teguina LR/lc
Subfamily: Sigmodontinae
Genus: Melanomys
 Dusky rice rat, Melanomys caliginosus LR/lc
Genus: Oligoryzomys
 Fulvous pygmy rice rat, Oligoryzomys fulvescens LR/lc
Genus: Oryzomys
 Alfaro's rice rat, Oryzomys alfaroi LR/lc
 Bolivar rice rat, Oryzomys bolivaris LR/lc
 Coues' rice rat, Oryzomys couesi LR/lc
 Nicaraguan rice rat, Oryzomys dimidiatus LR/nt
 Long-nosed rice rat, Oryzomys rostr