| Acanthaspidiidae Just, 2001 | | 10 | Species | Taxom |
| Acanthephyridae Dana, 1852 | | 43 | Species | Taxom |
| Acetidae Vereshchaka, 2017 | | 3 | Species | Taxom |
| Acidopsidae Stevcic, 2005 | | 5 | Species | Taxom |
| Aegidae White, 1850 | | 31 | Species | Taxom |
| Aeglidae Dana, 1852 | | 3 | Species | Taxom |
| Aethridae Dana, 1851 | | 5 | Species | Taxom |
| Agathotanaidae Lang, 1971 | | 10 | Species | Taxom |
| Akanthophoreidae Sieg, 1986 | | 2 | Species | Taxom |
| Albuneidae Stimpson, 1858 | Mole crabs | 17 | Species | Taxom |
| Allocrangonyctidae Holsinger, 1989 | | 20 | Species | Taxom |
| Alloniscidae Schmidt, 2003 | | 10 | Species | Taxom |
| Alpheidae Rafinesque, 1815 | Alpheid shrimp | 264 | Species | Taxom |
| Alvinocarididae Christoffersen, 1986 | | 4 | Species | Taxom |
| Amaryllididae Lowry & Stod..., 2002 | | 6 | Species | Taxom |
| Amathillopsidae Pirlot, 1934 | | 1 | Species | Taxom |
| Ampeliscidae Costa, 1857 | | 36 | Species | Taxom |
| Amphilochidae Boeck, 1871 | | 15 | Species | Taxom |
| Amphionididae Holthuis, 1955 | | 1 | Species | Taxom |
| Amphisopodidae Nicholls, 1943 | | 10 | Species | Taxom |
| Ampithoidae J. L. Barnard, 1965 | | 34 | Species | Taxom |
| Anapronoidae Bowman & Gruner, 1973 | | 1 | Species | Taxom |
| Anarthruridae Lang, 1971 | | 2 | Species | Taxom |
| Ancinidae Tattersall, 1905 | | 1 | Species | Taxom |
| Antarcturidae Kussakin & V..., 1998 | | 5 | Species | Taxom |
| Antheluridae Kensley & Sc..., 2000 | | 6 | Species | Taxom |
| Anthuridae Wägele, 1982 | | 72 | Species | Taxom |
| Aoridae Shoemaker, 1945 | | 51 | Species | Taxom |
| Aphanodactylidae Ahyong & Ng, 2009 | | 2 | Species | Taxom |
| Apseudellidae Gutu, 1972 | | 1 | Species | Taxom |
| Apseudidae Leach, 1814 | | 25 | Species | Taxom |
| Archaeoniscidae Haack, 1918 | | 0 | Species | Taxom |
| Archaeoscinidae Stebbing, 1904 | | 2 | Species | Taxom |
| Arcitalitridae Myers & Lowry, 2020 | | 0 | Species | Taxom |
| Arcturidae Dana, 1849 | | 54 | Species | Taxom |
| Arcturididae Poore, 2001 | | 1 | Species | Taxom |
| Argissidae Walker, 1904 | | 1 | Species | Taxom |
| Aristeidae Wood-Mason, 1891 | Gamba prawns | 21 | Species | Taxom |
| Aristiidae Lowry & Stod..., 1997 | | 3 | Species | Taxom |
| Armadillidae Brandt, 1831 | | 301 | Species | Taxom |
| Armadillidiidae Brandt, 1833 | Doodle bugs | 40 | Species | Taxom |
| Asconiscidae Bonnier, 1900 | | 1 | Species | Taxom |
| Asellidae Latreille, 1802 | Freshwater Isopods | 21 | Species | Taxom |
| Astacidae Latreille, 1802 | Astacid crayfishes | 6 | Species | Taxom |
| Atelecyclidae Ortmann, 1893 | Horse crabs | 8 | Species | Taxom |
| Atyidae De Haan, 1849 | Atyid shrimps | 129 | Species | Taxom |
| Atylidae Lilljeborg, 1865 | | 11 | Species | Taxom |
| Austrarcturellidae Poore & Bard..., 1992 | | 1 | Species | Taxom |
| Axiidae Huxley, 1879 | Lobster shrimps | 35 | Species | Taxom |
| Barbouriidae Christoffersen, 1987 | | 2 | Species | Taxom |
| Barybrotidae Hansen, 1890 | | 1 | Species | Taxom |
| Bateidae Stebbing, 1906 | | 2 | Species | Taxom |
| Bathynataliidae Poore, 2005 | | 2 | Species | Taxom |
| Bathynellidae Pennak & Ward, 1985 | | 1 | Species | Taxom |
| Bathypalaemonellidae de Saint Lau..., 1985 | | 2 | Species | Taxom |
| Bathysquillidae Manning, 1967 | Bathysquillid mantis shrimps | 1 | Species | Taxom |
| Bathytropidae Vandel, 1952 | | 2 | Species | Taxom |
| Benthesicymidae Wood-Mason, 1891 | Benthesicymid shrimps | 28 | Species | Taxom |
| Bentheuphausiidae Colosi, 1917 | | 1 | Species | Taxom |
| Blepharipodidae Boyko, 2002 | Spiny sand crabs | 1 | Species | Taxom |
| Bodotriidae T. Scott, 1901 | | 117 | Species | Taxom |
| Bogidiellidae Hertzog, 1936 | | 7 | Species | Taxom |
| Bolttsiidae Barnard & Ka..., 1987 | | 1 | Species | Taxom |
| Bopyridae Rafinesque, 1815 | | 79 | Species | Taxom |
| Bougisidae Zeidler, 2004 | | 1 | Species | Taxom |
| Brachyscelidae Stephensen, 1923 | | 0 | Species | Taxom |
| Bresiliidae Calman, 1896 | | 2 | Species | Taxom |
| Buddelundiellidae (G. O. Sars, 1899) | | 2 | Species | Taxom |
| Bythocarididae Christoffersen, 1987 | | 1 | Species | Taxom |
| Bythograeidae Williams, 1980 | | 1 | Species | Taxom |
| Cabiropidae Giard & Bonnier, 1887 | | 1 | Species | Taxom |
| Calappidae Milne-Edwards, 1837 | Box Crab | 57 | Species | Taxom |
| Callianassidae Dana, 1852 | Burrowing Ghost Shrimps | 77 | Species | Taxom |
| Callianideidae Kossmann, 1880 | | 3 | Species | Taxom |
| Callichiridae Manning & Fe..., 1991 | | 3 | Species | Taxom |
| Calliopiidae G. O. Sars, 1895 | | 11 | Species | Taxom |
| Cambaridae Hobbs, 1942 | Cambarid crayfishes | 16 | Species | Taxom |
| Camptandriidae Stimpson, 1858 | | 14 | Species | Taxom |
| Campylonotidae Sollaud, 1913 | | 2 | Species | Taxom |
| Cancridae Latreille, 1802 | Edible crabs | 21 | Species | Taxom |
| Capitoniscidae Boyko & Will..., 2023 | | 1 | Species | Taxom |
| Caprellidae Leach, 1814 | Ghost shrimps | 47 | Species | Taxom |
| Cardenioidae Barnard & Ka..., 1987 | | 1 | Species | Taxom |
| Carpiliidae Ortmann, 1893 | Coral crabs | 19 | Species | Taxom |
| Caryocarididae Racheboeuf, ..., 2000 | | 1 | Species | Taxom |
| Ceinidae J. L. Barnard, 1972 | | 4 | Species | Taxom |
| Cenomanocarcinidae Guinot & al., 2008 | | 1 | Species | Taxom |
| Ceratocumatidae Calman, 1905 | | 4 | Species | Taxom |
| Chaetiliidae Dana, 1849 | | 2 | Species | Taxom |
| Chasmocarcinidae Serène, 1964 | | 7 | Species | Taxom |
| Cheirocratidae Ren, 2006 | | 1 | Species | Taxom |
| Cheluridae Allman, 1847 | | 1 | Species | Taxom |
| Chirostylidae Ortmann, 1892 | | 44 | Species | Taxom |
| Chlorotocellidae Komai, Chan ..., 2019 | | 3 | Species | Taxom |
| Cirolanidae Dana, 1852 | Cave Isopods | 127 | Species | Taxom |
| Coenobitidae Dana, 1851 | Land hermit crabs | 19 | Species | Taxom |
| Coleiidae Van Straelen, 1924 | | 1 | Species | Taxom |
| Colletteidae Larsen & Wilson, 2002 | | 11 | Species | Taxom |
| Colomastigidae Stebbing, 1899 | | 7 | Species | Taxom |
| Coralaxiidae Sakai & de S..., 1989 | | 1 | Species | Taxom |
| Corallanidae Nunomura, 2006 | | 17 | Species | Taxom |
| Coronididae Manning, 1980 | Coronidid mantis shrimps | 3 | Species | Taxom |
| Corophiidae Leach, 1814 | | 25 | Species | Taxom |
| Corystidae Samouelle, 1819 | | 2 | Species | Taxom |
| Crangonidae Haworth, 1825 | Crangonid Shrimp | 62 | Species | Taxom |
| Crangonyctidae Bousfield, 1973 | Gammarid amphipods | 1 | Species | Taxom |
| Cryptochiridae Paulson, 1875 | Coral gall crabs | 15 | Species | Taxom |
| Cryptoniscidae Kossmann, 1880 | | 2 | Species | Taxom |
| Ctenochelidae Manning & Fe..., 1991 | | 1 | Species | Taxom |
| Cyamidae Rafinesque, 1815 | Whale lice | 8 | Species | Taxom |
| Cyclodorippidae Ortmann, 1892 | | 7 | Species | Taxom |
| Cyllopodidae Bovallius, 1887 | | 1 | Species | Taxom |
| Cymonomidae Bouvier, 1897 | | 5 | Species | Taxom |
| Cymothoidae Leach, 1818 | Fish Doctors | 81 | Species | Taxom |
| Cyphocarididae Lowry & Stod..., 1997 | | 5 | Species | Taxom |
| Cyproideidae J. L. Barnard, 1974 | | 5 | Species | Taxom |
| Cystisomatidae Willemöes-Suhm, 1875 | | 5 | Species | Taxom |
| Dacryopilumnidae Serène, 1984 | | 2 | Species | Taxom |
| Dairellidae Bovallius, 1887 | | 2 | Species | Taxom |
| Dairidae Ng & Rodriguez, 1986 | | 4 | Species | Taxom |
| Dajidae Giard & Bonnier, 1887 | | 6 | Species | Taxom |
| Dendrotiidae (Vanhöffen, 1914) | | 3 | Species | Taxom |
| Desmocarididae Borradaile, 1915 | | 4 | Species | Taxom |
| Desmosomatidae Brix, 2006 | | 23 | Species | Taxom |
| Dexaminidae Leach, 1814 | | 8 | Species | Taxom |
| Diastylidae Bate, 1856 | | 65 | Species | Taxom |
| Didymocheliidae Bellan-Santi..., 1986 | | 2 | Species | Taxom |
| Diogenidae Ortmann, 1892 | Left-handed hermit crabs | 174 | Species | Taxom |
| Disciadidae Rathbun, 1902 | | 5 | Species | Taxom |
| Dogielinotidae Gurjanova, 1953 | | 5 | Species | Taxom |
| Domeciidae Ortmann, 1893 | | 1 | Species | Taxom |
| Dorippidae MacLeay, 1838 | Demon-faced crabs | 30 | Species | Taxom |
| Dotillidae Stimpson, 1858 | | 5 | Species | Taxom |
| Dromiidae De Haan, 1833 | Sponge crabs | 89 | Species | Taxom |
| Dubioniscidae Vandel, 1953 | | 1 | Species | Taxom |
| Dynomenidae Ortmann, 1892 | | 11 | Species | Taxom |
| Echinothambematidae Menzies, 1962 | | 1 | Species | Taxom |
| Enoplometopidae de Saint Lau..., 1988 | Reef lobsters | 8 | Species | Taxom |
| Eophliantidae Sheard, 1936 | | 1 | Species | Taxom |
| Epialtidae MacLeay, 1838 | Kelp Crabs | 124 | Species | Taxom |
| Epimeriidae Boeck, 1871 | | 7 | Species | Taxom |
| Eriopisidae Lowry & Myers, 2013 | | 8 | Species | Taxom |
| Eriphiidae MacLeay, 1838 | | 2 | Species | Taxom |
| Erymidae Van Straelen, 1924 | | 8 | Species | Taxom |
| Erythrosquillidae Manning & Bruce, 1984 | | 1 | Species | Taxom |
| Etyidae Guinot & Tav..., 2001 | | 2 | Species | Taxom |
| Etyiidae (Guinot & Tav..., 2001) | | 0 | Species | Taxom |
| Eubelidae Taiti, Ferra..., 2000 | | 224 | Species | Taxom |
| Eucopiidae Sars, 1885 | | 7 | Species | Taxom |
| Eugonatonotidae Chace, 1937 | | 1 | Species | Taxom |
| Eulimnogammaridae Kamaltynov, 1999 | | 1 | Species | Taxom |
| Eumunididae A. Milne Edw..., 1900 | | 7 | Species | Taxom |
| Euphausiidae Milne-Edwards, 1837 | | 64 | Species | Taxom |
| Euryplacidae Stimpson, 1871 | | 7 | Species | Taxom |
| Eurypodiidae MacLeay, 1838 | | 1 | Species | Taxom |
| Euryrhynchidae Holthuis, 1950 | | 3 | Species | Taxom |
| Eurysquillidae Manning, 1977 | Eurysquillid mantis shrimps | 4 | Species | Taxom |
| Eusiridae Stebbing, 1888 | | 20 | Species | Taxom |
| Exoedicerotidae Barnard & Dr..., 1982 | | 1 | Species | Taxom |
| Expanathuridae Nunomura, 1984 | | 12 | Species | Taxom |
| Galatheidae Samouelle, 1819 | Squat lobsters | 78 | Species | Taxom |
| Gammarellidae Bousfield, 1977 | | 1 | Species | Taxom |
| Gammaridae Leach, 1813 | Gammarids | 59 | Species | Taxom |
| Gecarcinidae MacLeay, 1838 | Land crabs | 16 | Species | Taxom |
| Geryonidae Colosi, 1923 | Deepsea crabs | 27 | Species | Taxom |
| Glypheidae Zittel, 1885 | | 39 | Species | Taxom |
| Glyphocrangonidae Smith, 1884 | Armored shrimp | 18 | Species | Taxom |
| Glyptograpsidae Schubart, C..., 2002 | | 1 | Species | Taxom |
| Gnathiidae Leach, 1814 | | 45 | Species | Taxom |
| Gnathophausiidae Udrescu, 1984 | | 9 | Species | Taxom |
| Gnathostenetroididae Kussakin, 1967 | | 4 | Species | Taxom |
| Goneplacidae MacLeay, 1838 | Angular crabs | 34 | Species | Taxom |
| Gonodactylidae Giesbrecht, 1910 | Gonodactylid mantis shrimps | 55 | Species | Taxom |
| Grapsidae MacLeay, 1838 | Marsh crabs | 44 | Species | Taxom |
| Gynodiastylidae Stebbing, 1912 | | 6 | Species | Taxom |
| Hadromastacidae Bruce & Müller, 1991 | | 1 | Species | Taxom |
| Hadziidae Karaman, 1943 | | 3 | Species | Taxom |
| Halophilosciidae Verhoeff, 1908 | | 12 | Species | Taxom |
| Hapalogastridae Brandt, 1850 | | 1 | Species | Taxom |
| Haplomunnidae Wilson, 1976 | | 1 | Species | Taxom |
| Haploniscidae Hansen, 1916 | | 23 | Species | Taxom |
| Haustoriidae Stebbing, 1906 | | 2 | Species | Taxom |
| Hekelidae Ferrara, 1977 | | 1 | Species | Taxom |
| Hemisquillidae Manning, 1980 | Hemisquillid mantis shrimps | 1 | Species | Taxom |
| Hepatidae Stimpson, 1871 | | 5 | Species | Taxom |
| Hexapodidae Miers, 1886 | | 13 | Species | Taxom |
| Hippidae Latreille, 1825 | Mole Crabs | 16 | Species | Taxom |
| Hippolytidae Dana, 1852 | Anemone shrimp | 60 | Species | Taxom |
| Holidoteidae Wägele, 1989 | | 10 | Species | Taxom |
| Holognathidae G. Thomson, 1904 | | 3 | Species | Taxom |
| Homolidae De Haan, 1839 | Carrier crabs | 26 | Species | Taxom |
| Homolodromiidae Alcock, 1899 | | 4 | Species | Taxom |
| Hyalidae Bulycheva, 1957 | | 37 | Species | Taxom |
| Hymenosomatidae MacLeay, 1838 | | 16 | Species | Taxom |
| Hyperiidae Dana, 1853 | Hyperiids | 10 | Species | Taxom |
| Hyperiopsidae Bovallius, 1886 | | 1 | Species | Taxom |
| Hyssuridae Wägele, 1981 | | 7 | Species | Taxom |
| Idoteidae Samouelle, 1819 | | 28 | Species | Taxom |
| Inachidae MacLeay, 1838 | | 84 | Species | Taxom |
| Inachoididae Dana, 1851 | | 10 | Species | Taxom |
| Indosquillidae Manning, 1995 | | 1 | Species | Taxom |
| Ingolfiellidae Hansen, 1903 | | 4 | Species | Taxom |
| Iphiculidae Alcock, 1896 | | 2 | Species | Taxom |
| Iphimediidae Boeck, 1871 | | 9 | Species | Taxom |
| Irmaosidae Ferrara & Taiti, 1983 | | 2 | Species | Taxom |
| Isaeidae Dana, 1853 | | 40 | Species | Taxom |
| Ischnomesidae Hansen, 1916 | | 9 | Species | Taxom |
| Ischyroceridae Stebbing, 1899 | | 32 | Species | Taxom |
| Iulopididae Zeidler, 2004 | | 1 | Species | Taxom |
| Jaeropsidae (Nordenstam, 1933) | | 1 | Species | Taxom |
| Janirellidae Menzies, 1956 | | 5 | Species | Taxom |
| Janiridae Sars, 1897 | | 38 | Species | Taxom |
| Joeropsididae Nordenstam, 1933 | | 23 | Species | Taxom |
| Julmarichardiidae Moralés-Núñe..., 2021 | | 2 | Species | Taxom |
| Kalliapseudidae Lang, 1956 | | 6 | Species | Taxom |
| Kamakidae Myers & Lowry, 2003 | | 4 | Species | Taxom |
| Katianiridae Svavarsson, 1987 | | 1 | Species | Taxom |
| Koonungidae Sayce, 1908 | | 1 | Species | Taxom |
| Lampropidae Sars, 1878 | | 30 | Species | Taxom |
| Lanceolidae Bovallius, 1887 | | 7 | Species | Taxom |
| Laomediidae Borradaile, 1903 | | 3 | Species | Taxom |
| Latreilliidae Stimpson, 1858 | Longleg crabs | 4 | Species | Taxom |
| Lepidomysidae Clarke, 1961 | | 1 | Species | Taxom |
| Leptanthuridae Poore, 2001 | | 26 | Species | Taxom |
| Leptocheliidae Lang, 1973 | | 23 | Species | Taxom |
| Leptognathiidae Sieg, 1976 | | 2 | Species | Taxom |
| Lestrigonidae Zeidler, 2004 | | 4 | Species | Taxom |
| Leuconidae Sars, 1878 | | 35 | Species | Taxom |
| Leucosiidae Samouelle, 1819 | Nut crabs | 139 | Species | Taxom |
| Leucothoidae Dana, 1852 | | 18 | Species | Taxom |
| Ligiidae Leach, 1814 | Rock lice | 14 | Species | Taxom |
| Liljeborgiidae Stebbing, 1899 | | 15 | Species | Taxom |
| Limnoriidae White, 1850 | Gribble | 13 | Species | Taxom |
| Linnaeoxanthidae Stevcic, 2005 | | 1 | Species | Taxom |
| Lithodidae Samouelle, 1819 | King crab | 21 | Species | Taxom |
| Litocheiridae ?tev?i?, 2005 | | 1 | Species | Taxom |
| Lomisidae Bouvier, 1895 | | 1 | Species | Taxom |
| Lophogastridae Sars, 1870 | | 9 | Species | Taxom |
| Luciferidae De Haan, 1849 | | 6 | Species | Taxom |
| Lycaeidae Claus, 1879 | | 10 | Species | Taxom |
| Lysianassidae Dana, 1849 | | 78 | Species | Taxom |
| Lysiosquillidae Giesbrecht, 1910 | Lysiosquillid mantis shrimps | 16 | Species | Taxom |
| Lysmatidae Dana, 1852 | | 27 | Species | Taxom |
| Macrophthalmidae Dana, 1851 | | 28 | Species | Taxom |
| Macrostylidae Hansen, 1916 | | 11 | Species | Taxom |
| Maeridae Krapp-Schickel, 2008 | | 18 | Species | Taxom |
| Majidae Samouelle, 1819 | Spider crab | 86 | Species | Taxom |
| Marocarcinidae Guinot, De A..., 2008 | | 1 | Species | Taxom |
| Mathildellidae Karasawa & Kato, 2003 | | 3 | Species | Taxom |
| Matutidae De Haan, 1835 | | 13 | Species | Taxom |
| Maxillipiidae Ledoyer, 1973 | | 2 | Species | Taxom |
| Mecochiridae Van Straelen, 1924 | | 1 | Species | Taxom |
| Megaluropidae Thomas & Bar..., 1987 | | 4 | Species | Taxom |
| Melitidae Bousfield, 1973 | | 85 | Species | Taxom |
| Menippidae Ortmann, 1893 | Stone crabs | 31 | Species | Taxom |
| Merguiidae Christoffersen, 1990 | | 2 | Species | Taxom |
| Metacrangonyctidae Boutin & Mis..., 1988 | | 3 | Species | Taxom |
| Metapseudidae Lang, 1970 | | 5 | Species | Taxom |
| Micheleidae Sakai, 1992 | | 5 | Species | Taxom |
| Microcerberidae Karaman, 1933 | | 9 | Species | Taxom |
| Microparasellidae Karaman, 1933 | | 6 | Species | Taxom |
| Microphasmatidae (Stephensen &..., 1931) | | 1 | Species | Taxom |
| Micruropodidae Kamaltynov, 1999 | | 1 | Species | Taxom |
| Mictosomatidae Wolff, 1965 | | 1 | Species | Taxom |
| Mictyridae Dana, 1851 | | 1 | Species | Taxom |
| Mimonectidae Bovallius, 1885 | | 3 | Species | Taxom |
| Mithracidae Balss, 1929 | | 16 | Species | Taxom |
| Monodellidae Taramelli, 1954 | | 4 | Species | Taxom |
| Munididae Ahyong, Baba..., 2010 | | 75 | Species | Taxom |
| Munidopsidae Whiteaves, 1874 | | 66 | Species | Taxom |
| Munnidae Sars, 1897 | | 15 | Species | Taxom |
| Munnopsidae Lilljeborg, 1864 | | 51 | Species | Taxom |
| Mysidae Haworth, 1825 | | 146 | Species | Taxom |
| Nannastacidae Spence Bate, 1866 | | 142 | Species | Taxom |
| Nannoniscidae Hansen, 1916 | | 10 | Species | Taxom |
| Nannosquillidae Manning, 1980 | Nannosquillid mantis shrimps | 14 | Species | Taxom |
| Nanocassiopidae Števčić, 2013 | | 1 | Species | Taxom |
| Nebaliidae Samouelle, 1819 | | 12 | Species | Taxom |
| Nebaliopsididae Hessler, 1984 | | 1 | Species | Taxom |
| Necrocarcinidae Föster, 1968 | | 2 | Species | Taxom |
| Nematocarcinidae Smith, 1884 | | 13 | Species | Taxom |
| Neomegamphopidae Myers, 1981 | | 3 | Species | Taxom |
| Neotanaidae Lang, 1956 | | 7 | Species | Taxom |
| Nephropidae Dana, 1852 | Clawed Lobster | 25 | Species | Taxom |
| Niphargidae Bousfield, 1977 | | 2 | Species | Taxom |
| Nototanaidae Sieg, 1976 | | 12 | Species | Taxom |
| Ochlesidae Stebbing, 1910 | | 2 | Species | Taxom |
| Ocypodidae Rafinesque, 1815 | Fiddler crabs | 79 | Species | Taxom |
| Odontodactylidae Manning, 1980 | Odontodactylid mantis shrimps | 6 | Species | Taxom |
| Oedicerotidae Lilljeborg, 1865 | | 20 | Species | Taxom |
| Ogyrididae Holthuis, 1955 | Long-eyed shrimps | 4 | Species | Taxom |
| Olibrinidae Vandel, 1973 | | 7 | Species | Taxom |
| Oniscidae Latreille, 1802 | Sow Bugs | 12 | Species | Taxom |
| Oplophoridae Dana, 1852 | Deepsea shrimps | 16 | Species | Taxom |
| Oregoniidae Garth, 1958 | | 3 | Species | Taxom |
| Oxycephalidae Dana, 1852 | | 8 | Species | Taxom |
| Oziidae Dana, 1851 | | 12 | Species | Taxom |
| Pagurapseudidae Lang, 1970 | | 3 | Species | Taxom |
| Paguridae Latreille, 1802 | Hermit Crabs | 135 | Species | Taxom |
| Palaemonidae Rafinesque, 1815 | Palaemonid Shrimps | 396 | Species | Taxom |
| Paleoxanthopsidae Schweitzer, 2003 | | 1 | Species | Taxom |
| Palicidae Bouvier, 1898 | Stilt crabs | 15 | Species | Taxom |
| Palinuridae Latreille, 1802 | Crawfish | 53 | Species | Taxom |
| Pallaseidae Tachteew, 2000 | | 0 | Species | Taxom |
| Pandalidae Haworth, 1825 | Pandalid shrimp | 64 | Species | Taxom |
| Panopeidae Ortmann, 1893 | Mud crabs | 9 | Species | Taxom |
| Parabathynellidae Cho, 1996 | | 6 | Species | Taxom |
| Paramelitidae Bousfield, 1977 | | 7 | Species | Taxom |
| Paramunnidae Vanhöffen, 1914 | | 16 | Species | Taxom |
| Paranthuridae Menzies & Glynn, 1968 | | 20 | Species | Taxom |
| Parapaguridae S. I. Smith, 1882 | Deepwater hermit crabs | 34 | Species | Taxom |
| Paraphronimidae Bovallius, 1887 | | 2 | Species | Taxom |
| Parapseudidae Gutu, 1981 | | 5 | Species | Taxom |
| Parascelidae Bovallius, 1887 | | 5 | Species | Taxom |
| Parasquillidae Manning, 1995 | | 3 | Species | Taxom |
| Parastacidae Huxley, 1879 | | 19 | Species | Taxom |
| Paratanaidae Lang, 1949 | | 4 | Species | Taxom |
| Parathelphusidae Alcock, 1910 | | 7 | Species | Taxom |
| Pardaliscidae Boeck, 1871 | | 8 | Species | Taxom |
| Parthenopidae MacLeay, 1838 | Elbow crabs | 82 | Species | Taxom |
| Pasiphaeidae Dana, 1852 | Glass shrimps | 30 | Species | Taxom |
| Penaeidae Rafinesque, 1815 | Penaeid shrimps | 119 | Species | Taxom |
| Periscyphicidae Ferrara, 1973 | | 1 | Species | Taxom |
| Petalidiumidae Vereshchaka, 2017 | | 2 | Species | Taxom |
| Petalophthalmidae Czerniavsky, 1882 | | 2 | Species | Taxom |
| Philosciidae Kinahan, 1857 | Woodlice | 149 | Species | Taxom |
| Phliantidae Stebbing, 1899 | | 3 | Species | Taxom |
| Photidae (Boeck, 1871) | | 2 | Species | Taxom |
| Phoxocephalidae Sars, 1891 | | 19 | Species | Taxom |
| Phreatoicidae Chilton, 1891 | | 1 | Species | Taxom |
| Phronimidae Rafinesque, 1815 | | 6 | Species | Taxom |
| Phrosinidae Dana, 1852 | | 3 | Species | Taxom |
| Physetocarididae Chace, 1940 | | 1 | Species | Taxom |
| Pilumnidae Samouelle, 1819 | | 98 | Species | Taxom |
| Pilumnoididae Guinot & Mac..., 1987 | | 4 | Species | Taxom |
| Pinnotheridae De Haan, 1833 | Commensal Crabs | 51 | Species | Taxom |
| Pirimelidae Alcock, 1899 | | 3 | Species | Taxom |
| Plagusiidae Dana, 1851 | | 20 | Species | Taxom |
| Planopilumnidae Serène, 1984 | | 2 | Species | Taxom |
| Platyarthridae Verhoeff, 1949 | Woodlice | 56 | Species | Taxom |
| Platyischnopidae Barnard & Dr..., 1979 | | 2 | Species | Taxom |
| Platyscelidae Bate, 1862 | | 11 | Species | Taxom |
| Platyxanthidae Guinot, 1977 | | 2 | Species | Taxom |
| Pleioplateidae Barnard, 1978 | | 1 | Species | Taxom |
| Pleurocopidae Fresi & Schi..., 1972 | | 1 | Species | Taxom |
| Pleustidae Bucholz, 1874 | | 3 | Species | Taxom |
| Podoceridae Leach, 1814 | | 16 | Species | Taxom |
| Polychelidae Wood-Mason, 1874 | Blind lobsters | 21 | Species | Taxom |
| Pontogeneiidae Stebbing, 1906 | | 5 | Species | Taxom |
| Pontoporeiidae Dana, 1853 | | 12 | Species | Taxom |
| Porcellanidae Haworth, 1825 | Porcelain crab | 97 | Species | Taxom |
| Porcellionidae Brandt & Rat..., 1831 | Woodlice | 212 | Species | Taxom |
| Portunidae Rafinesque, 1815 | Swimming Crab | 282 | Species | Taxom |
| Potamidae Ortmann, 1896 | | 76 | Species | Taxom |
| Potamonautidae Bott, 1970 | | 150 | Species | Taxom |
| Procarididae Chace & Manning, 1972 | | 1 | Species | Taxom |
| Processidae Ortmann, 1896 | Night shrimps | 39 | Species | Taxom |
| Pronoidae Dana, 1852 | | 7 | Species | Taxom |
| Proscinidae Pirlot, 1933 | | 1 | Species | Taxom |
| Protojaniridae Fresi, Idat..., 1980 | | 9 | Species | Taxom |
| Protorchestiidae Myers & Lowry, 2020 | | 4 | Species | Taxom |
| Protosquillidae Manning, 1980 | Protosquillid mantis shrimps | 13 | Species | Taxom |
| Psalidopodidae Wood-Mason, 1892 | Scissorfoot shrimps | 1 | Species | Taxom |
| Psammocarcinidae | | 1 | Species | Taxom |
| Pseudocarcinidae Ng & Davie, 2020 | | 0 | Species | Taxom |
| Pseudocumatidae G. O. Sars, 1878 | | 6 | Species | Taxom |
| Pseudojaniridae Wilson, 1986 | | 2 | Species | Taxom |
| Pseudorhombilidae Alcock, 1900 | | 3 | Species | Taxom |
| Pseudosquillidae Manning, 1977 | Pseudosquillid mantis shrimps | 11 | Species | Taxom |
| Pseudotanaidae Sieg, 1976 | | 3 | Species | Taxom |
| Pseudothelphusidae Ortmann, 1893 | | 9 | Species | Taxom |
| Pseudoziidae Alcock, 1898 | | 3 | Species | Taxom |
| Pudeoniscidae Lemos de Castro, 1973 | | 2 | Species | Taxom |
| Pylochelidae Bate, 1888 | | 6 | Species | Taxom |
| Raninidae De Haan, 1839 | Frog crabs | 26 | Species | Taxom |
| Retroplumidae Gill, 1894 | | 2 | Species | Taxom |
| Rhabdochiridae Richardson, 1905 | | 1 | Species | Taxom |
| Rhynchocinetidae Ortmann, 1890 | Hingebeak shrimp | 16 | Species | Taxom |
| Rhyscotidae Budde-Lund, 1908 | | 10 | Species | Taxom |
| Salentinellidae Bousfield, 1977 | | 2 | Species | Taxom |
| Santiidae Wilson, 1987 | | 11 | Species | Taxom |
| Scalopidiidae Stevcic, 2005 | | 0 | Species | Taxom |
| Schoebliidae Verhoeff, 1938 | | 2 | Species | Taxom |
| Scinidae Stebbing, 1888 | | 10 | Species | Taxom |
| Scleropactidae Verhoeff, 1938 | | 12 | Species | Taxom |
| Scopelocheiridae Lowry & Stod..., 1997 | | 3 | Species | Taxom |
| Scyllaridae Latreille, 1825 | Shovel-nosed lobsters | 65 | Species | Taxom |
| Scyphacidae Dana, 1852 | | 9 | Species | Taxom |
| Sebidae Walker, 1908 | | 2 | Species | Taxom |
| Sergestidae Dana, 1852 | | 77 | Species | Taxom |
| Serolidae Dana, 1852 | | 14 | Species | Taxom |
| Sesarmidae Dana, 1851 | | 97 | Species | Taxom |
| Sicyonellidae Vereshchaka, 2017 | | 1 | Species | Taxom |
| Sicyoniidae Ortmann, 1898 | Rock shrimps | 19 | Species | Taxom |
| Solenoceridae Wood-Mason, 1891 | Solenocerid shrimps | 45 | Species | Taxom |
| Spelaeogriphidae Gordon, 1957 | | 1 | Species | Taxom |
| Spelaeoniscidae Vandel, 1948 | | 11 | Species | Taxom |
| Sphaeromatidae Latreille, 1825 | | 174 | Species | Taxom |
| Sphyrapidae Gutu, 1980 | | 3 | Species | Taxom |
| Spongicolidae von Martens, 1872 | Glass sponge shrimps | 12 | Species | Taxom |
| Squillidae Latreille, 1802 | Squillid mantis shrimps | 81 | Species | Taxom |
| Stegocephalidae Dana, 1852 | | 14 | Species | Taxom |
| Stenasellidae Dudich, 1924 | | 24 | Species | Taxom |
| Stenetriidae Hansen, 1905 | | 31 | Species | Taxom |
| Stenoniscidae Budde-Lund, 1904 | | 2 | Species | Taxom |
| Stenopodidae Risso, 1826 | Coral shrimps | 13 | Species | Taxom |
| Stenothoidae Boeck, 1871 | | 19 | Species | Taxom |
| Sternophysingidae Holsinger, 1992 | | 3 | Species | Taxom |
| Sternostylidae Baba Ahyong ..., 2018 | | 1 | Species | Taxom |
| Stilipididae Holmes, 1908 | | 3 | Species | Taxom |
| Strahlaxiidae Poore, 1994 | | 3 | Species | Taxom |
| Stylodactylidae Bate, 1888 | | 6 | Species | Taxom |
| Styloniscidae Vandel, 1952 | | 27 | Species | Taxom |
| Synopiidae Dana, 1852 | | 9 | Species | Taxom |
| Takuidae Manning, 1995 | | 4 | Species | Taxom |
| Talitridae Rafinesque, 1815 | Beach Hoppers | 55 | Species | Taxom |
| Tanaellidae Larsen & Wilson, 2002 | | 4 | Species | Taxom |
| Tanaidae Dana, 1849 | | 23 | Species | Taxom |
| Tanaocheleidae Ng & P. F. C..., 2000 | | 1 | Species | Taxom |
| Tanzanapseudidae Bacescu, 1975 | | 3 | Species | Taxom |
| Temnophliantidae Griffiths, 1975 | | 2 | Species | Taxom |
| Tetraliidae Castro, Ng &..., 2004 | | 14 | Species | Taxom |
| Tetrasquillidae Manning & Camp, 1993 | Tetrasquillid mantis shrimps | 4 | Species | Taxom |
| Tetriasidae Tsang & Naruse, 2023 | | 0 | Species | Taxom |
| Thalassinidae Latreille, 1831 | Mud lobsters | 1 | Species | Taxom |
| Thambematidae Stebbing, 1913 | | 1 | Species | Taxom |
| Thermosbaenidae Monod, 1927 | | 1 | Species | Taxom |
| Thiidae Dana, 1852 | | 4 | Species | Taxom |
| Thoridae Kingsley, 1878 | Anemone shrimp | 12 | Species | Taxom |
| Titaniidae Verhoeff, 1938 | | 6 | Species | Taxom |
| Trachelipodidae Strouhal, 1953 | | 21 | Species | Taxom |
| Trapeziidae Miers, 1886 | Coral crabs | 31 | Species | Taxom |
| Trichodactylidae H. Milne-Edw..., 1835 | | 6 | Species | Taxom |
| Trichoniscidae G. O. Sars, 1899 | Woodlice | 37 | Species | Taxom |
| Tridentellidae Bruce, 1984 | | 2 | Species | Taxom |
| Tumidocarcinidae Schweitzer, 2005 | | 3 | Species | Taxom |
| Tylidae Dana, 1852 | | 11 | Species | Taxom |
| Typhlocarididae Annandale & ..., 1913 | | 1 | Species | Taxom |
| Typhlotanaidae (Sieg, 1986) | | 4 | Species | Taxom |
| Tyrannophontidae Schram, 1984 | | 1 | Species | Taxom |
| Unciolidae Myers & Lowry, 2003 | | 1 | Species | Taxom |
| Upogebiidae Borradaile, 1903 | Mud shrimp | 34 | Species | Taxom |
| Uristidae Hurley, 1963 | | 10 | Species | Taxom |
| Urohaustoriidae Barnard & Dr..., 1982 | | 1 | Species | Taxom |
| Urothoidae Bousfield, 1978 | | 12 | Species | Taxom |
| Varunidae H. Milne-Edw..., 1853 | | 39 | Species | Taxom |
| Vibiliidae Dana, 1852 | | 6 | Species | Taxom |
| Xanthidae MacLeay, 1838 | Mud crabs | 365 | Species | Taxom |
| Xenophthalmidae Stimpson, 1858 | | 0 | Species | Taxom |
| Xiphocarididae Ortmann, 1895 | | 1 | Species | Taxom |
