| Acaridae Latreille, 1802 | Acarid mites | 54 | Species | Taxom |
| Achipteriidae Thor, 1929 | | 7 | Species | Taxom |
| Aeroglyphidae Zakhvatkin, 1941 | | 1 | Species | Taxom |
| Agelenidae C. L. Koch, 1837 | Agelenid Spiders | 597 | Species | Taxom |
| Alloptidae Gaud, 1957 | | 1 | Species | Taxom |
| Amaurobiidae Thorell, 1870 | Amaurobiids | 39 | Species | Taxom |
| Amblyommidae Banks, 1907 | | 24 | Species | Taxom |
| Ameridae Grandjean, 1965 | | 2 | Species | Taxom |
| Ameroseiidae Evans, 1961 | | 21 | Species | Taxom |
| Analgidae Trouessart &..., 1884 | Feather mites | 6 | Species | Taxom |
| Anapidae Simon, 1895 | Anapid spiders | 15 | Species | Taxom |
| Anyphaenidae Bertkau, 1878 | Anyphaenid sac spiders | 22 | Species | Taxom |
| Araneidae Simon, 1895 | Golden orb web spiders | 558 | Species | Taxom |
| Archaeidae C. L. Koch &..., 1854 | Archaeid spiders | 1 | Species | Taxom |
| Argasidae C. L. Koch, 1844 | Soft tick | 7 | Species | Taxom |
| Arrenuridae Thor, 1900 | | 19 | Species | Taxom |
| Ascidae Oudemans, 1905 | | 29 | Species | Taxom |
| Assamiidae Sørensen, 1884 | | 1 | Species | Taxom |
| Astegistidae Balogh, 1961 | | 3 | Species | Taxom |
| Atemnidae Chamberlin, 1931 | | 4 | Species | Taxom |
| Atopomelidae Fain, 1972 | | 3 | Species | Taxom |
| Aturidae Thor, 1900 | | 1 | Species | Taxom |
| Atypidae Thorell, 1870 | Atypical tarantulas | 26 | Species | Taxom |
| Autognetidae Grandjean, 1960 | | 1 | Species | Taxom |
| Avenzoariidae Oudemans, 1905 | | 1 | Species | Taxom |
| Basilobelbidae Balogh, 1961 | | 1 | Species | Taxom |
| Bdellidae Dugès, 1834 | Snout Mites | 13 | Species | Taxom |
| Belboidae | | 1 | Species | Taxom |
| Biantidae Thorell, 1889 | | 1 | Species | Taxom |
| Blattisociidae (Garman, 1948) | | 49 | Species | Taxom |
| Brachychthoniidae Thor, 1934 | | 5 | Species | Taxom |
| Buthidae C. L. Koch, 1837 | Arrowbreasted scorpions | 24 | Species | Taxom |
| Calcitronidae Petrunkevitch, 1945 | | 1 | Species | Taxom |
| Caleremaeidae Grandjean, 1965 | | 2 | Species | Taxom |
| Caligonellidae Grandjean, 1944 | | 6 | Species | Taxom |
| Caloppiidae (Balogh, 1960) | | 1 | Species | Taxom |
| Camerobiidae Southcott, 1957 | Stilt-legged mites | 4 | Species | Taxom |
| Camisiidae Oudemans, 1900 | | 3 | Species | Taxom |
| Canestriniidae Berlese, 1884 | | 12 | Species | Taxom |
| Caponiidae Simon, 1890 | Caponiid spiders | 3 | Species | Taxom |
| Carabodidae Koch, 1837 | | 13 | Species | Taxom |
| Carbolohmanniidae | | 1 | Species | Taxom |
| Carpoglyphidae Oudemans, 1923 | Driedfruit mites | 3 | Species | Taxom |
| Celaenopsidae Berlese, 1892 | | 4 | Species | Taxom |
| Cepheusidae Berlese, 1896 | | 3 | Species | Taxom |
| Ceratokalummidae Balogh, 1970 | | 1 | Species | Taxom |
| Ceratoppiidae (Kunst, 1971) | | 6 | Species | Taxom |
| Ceratozetidae Jacot, 1925 | | 18 | Species | Taxom |
| Chaerilidae Pocock, 1893 | | 8 | Species | Taxom |
| Chamobatidae Thor, 1937 | | 2 | Species | Taxom |
| Charontidae Simon, 1892 | | 2 | Species | Taxom |
| Cheiracanthiidae Wagner, 1887 | Eutichurid Spiders | 1 | Species | Taxom |
| Cheiridiidae Hansen, 1893 | | 2 | Species | Taxom |
| Cheliferidae Risso, 1826 | | 11 | Species | Taxom |
| Chernetidae Menge, 1855 | | 21 | Species | Taxom |
| Cheyletidae Leach, 1815 | | 64 | Species | Taxom |
| Chirodiscidae Trouessart, 1892 | | 4 | Species | Taxom |
| Chortoglyphidae Berlese, 1897 | | 1 | Species | Taxom |
| Chthoniidae Daday, 1888 | | 20 | Species | Taxom |
| Cladonychiidae (Hadži, 1935) | | 1 | Species | Taxom |
| Cloacaridae Camin, Moss,..., 1967 | | 1 | Species | Taxom |
| Clubionidae Wagner, 1887 | Clubiones | 234 | Species | Taxom |
| Corinnidae Karsch, 1880 | Ant-like Sac Spiders | 289 | Species | Taxom |
| Crotoniidae Thorell, 1876 | | 3 | Species | Taxom |
| Cryptognathidae Luxton, 1973 | | 1 | Species | Taxom |
| Ctenidae Keyserling, 1877 | Tropical wolf spiders | 23 | Species | Taxom |
| Ctenizidae Thorell, 1887 | Cork-lid trapdoor spider | 27 | Species | Taxom |
| Ctenobelbidae Grandjean, 1965 | | 1 | Species | Taxom |
| Cunaxidae Thor, 1902 | Predatory Mites | 22 | Species | Taxom |
| Cybaeidae Banks, 1892 | Pond Water Spiders | 12 | Species | Taxom |
| Cymbaeremaeidae Sellnick, 1928 | | 5 | Species | Taxom |
| Daesiidae Kraepelin, 1899 | | 3 | Species | Taxom |
| Damaeidae Berlese, 1896 | | 26 | Species | Taxom |
| Damaeolidae Grandjean, 1965 | | 2 | Species | Taxom |
| Deinopidae C. L. Koch, 1850 | Net-casters | 6 | Species | Taxom |
| Demodecidae Nicolet, 1855 | Follicle mites | 13 | Species | Taxom |
| Dermanyssidae Kolenati, 1859 | Dermanyssid mites | 20 | Species | Taxom |
| Dermoglyphidae Mégnin & Tro..., 1884 | | 1 | Species | Taxom |
| Desidae Pocock, 1895 | Desid spiders | 4 | Species | Taxom |
| Dicranolasmatidae Simon, 1879 | | 1 | Species | Taxom |
| Dictynidae O. P-Cambridge, 1871 | Dictynid spiders | 136 | Species | Taxom |
| Digamasellidae Evans, 1957 | | 9 | Species | Taxom |
| Dinychidae Berlese, 1916 | | 1 | Species | Taxom |
| Dipluridae Simon, 1889 | Curtainweb Spiders | 1 | Species | Taxom |
| Diptilomiopidae Boczek, 1964 | | 85 | Species | Taxom |
| Dolichocybidae Mahunka, 1970 | | 2 | Species | Taxom |
| Dysderidae C. L. Koch, 1837 | Dysderid spiders | 10 | Species | Taxom |
| Echimyopodidae Fain, 1967 | | 2 | Species | Taxom |
| Epedanidae Sørensen, 1886 | | 12 | Species | Taxom |
| Epicriidae Berlese, 1885 | | 5 | Species | Taxom |
| Epidermoptidae Trouessart, 1892 | | 1 | Species | Taxom |
| Epilohmanniidae Oudemans, 1923 | | 2 | Species | Taxom |
| Eremaeidae Oudemans, 1900 | | 3 | Species | Taxom |
| Eremaeozetidae Piffl, 1972 | | 3 | Species | Taxom |
| Eremellidae Balogh, 1961 | | 1 | Species | Taxom |
| Eremobatidae Kraepelin, 1899 | | 1 | Species | Taxom |
| Eremobelbidae Balogh, 1961 | | 7 | Species | Taxom |
| Eremulidae Grandjean, 1965 | | 4 | Species | Taxom |
| Eresidae C. L. Koch, 1851 | Eresid spiders | 10 | Species | Taxom |
| Ereynetidae Schrank, 1776 | | 2 | Species | Taxom |
| Eriophyidae Nalepa, 1898 | Blister mites | 396 | Species | Taxom |
| Erythraeidae Oudemans, 1902 | | 19 | Species | Taxom |
| Euagridae (Raven, 1979) | | 1 | Species | Taxom |
| Eukoeneniidae Condé, 1965 | | 1 | Species | Taxom |
| Eupalopsellidae Willmann, 1952 | | 5 | Species | Taxom |
| Euphthiracaridae Jacot, 1930 | | 8 | Species | Taxom |
| Euscorpiidae Laurie, 1896 | Shorttail scorpions | 26 | Species | Taxom |
| Eviphididae Berlese, 1913 | | 28 | Species | Taxom |
| Eylaidae Leach, 1815 | | 4 | Species | Taxom |
| Falculiferidae Oudemans, 1905 | | 2 | Species | Taxom |
| Feltriidae Viets, 1926 | | 1 | Species | Taxom |
| Filistatidae Ausserer, 1867 | Crevice weaver | 24 | Species | Taxom |
| Fortuyniidae Hammen, 1963 | | 1 | Species | Taxom |
| Freyanidae Dubinin, 1953 | | 1 | Species | Taxom |
| Galeodidae Sundevall, 1833 | | 10 | Species | Taxom |
| Galumnellidae Piffl, 1970 | | 4 | Species | Taxom |
| Galumnidae Jacot, 1925 | | 33 | Species | Taxom |
| Garypidae Simon, 1879 | | 2 | Species | Taxom |
| Gastronyssidae Fain, 1956 | | 1 | Species | Taxom |
| Geogarypidae Chamberlin, 1930 | | 3 | Species | Taxom |
| Glycyphagidae De Geer, 1778 | | 13 | Species | Taxom |
| Gnaphosidae Pocock, 1898 | Flat-bellied ground spiders | 316 | Species | Taxom |
| Granuloppiidae Balogh, 1983 | | 2 | Species | Taxom |
| Gustaviidae Oudemans, 1900 | | 1 | Species | Taxom |
| Gylippidae Lawrence, 1968 | | 1 | Species | Taxom |
| Gymnodamaeidae Grandjean, 1954 | | 4 | Species | Taxom |
| Haemogamasidae Oudemans, 1939 | | 3 | Species | Taxom |
| Hahniidae Bertkau, 1878 | Dwarf sheet spiders | 57 | Species | Taxom |
| Halacaridae Murray, 1877 | Sea mites | 3 | Species | Taxom |
| Halarachnidae Oudemans, 1906 | | 1 | Species | Taxom |
| Halonoproctidae Pocock, 1901 | | 13 | Species | Taxom |
| Haplozetidae Grandjean, 1936 | | 15 | Species | Taxom |
| Hemileiidae (J. & P. Balogh, 1984) | | 4 | Species | Taxom |
| Hermanniellidae Grandjean, 1934 | | 2 | Species | Taxom |
| Hermanniidae Sellnick, 1928 | | 7 | Species | Taxom |
| Hersiliidae Thorell, 1870 | Hersiliids | 20 | Species | Taxom |
| Heterobelbidae Balogh, 1961 | | 1 | Species | Taxom |
| Heterocheylidae Trägårdh, 1950 | | 2 | Species | Taxom |
| Heterocoptidae Fain, 1967 | | 2 | Species | Taxom |
| Hexathelidae Simon, 1892 | Australian funnelweb spiders | 31 | Species | Taxom |
| Histiostomatidae Berlese, 1897 | | 2 | Species | Taxom |
| Homocaligidae Wood, 1969 | | 2 | Species | Taxom |
| Hormuridae Laurie, 1896 | | 2 | Species | Taxom |
| Hubbardiidae Cook, 1899 | Hubbardiid shorttailed whipscorpions | 5 | Species | Taxom |
| Humerobatidae Grandjean, 1970 | | 3 | Species | Taxom |
| Hungarobelbidae (Miko & Travé, 1996) | | 2 | Species | Taxom |
| Hyadesiidae Halbert, 1915 | | 2 | Species | Taxom |
| Hydrachnidae Leach, 1815 | | 9 | Species | Taxom |
| Hydrodromidae Viets, 1936 | | 1 | Species | Taxom |
| Hydrovolziidae Thor, 1905 | | 1 | Species | Taxom |
| Hydryphantidae Piersig, 1896 | | 12 | Species | Taxom |
| Hygrobatidae Koch, 1842 | | 25 | Species | Taxom |
| Hypochilidae Marx, 1888 | Lampshade spiders | 23 | Species | Taxom |
| Hypochthoniidae Berlese, 1910 | | 4 | Species | Taxom |
| Hypoderatidae (Murray, 1877) | | 1 | Species | Taxom |
| Iolinidae Pritchard, 1956 | | 1 | Species | Taxom |
| Ischyropsalididae Simon, 1879 | | 2 | Species | Taxom |
| Ixodidae C. L. Koch, 1844 | Hard Tick | 47 | Species | Taxom |
| Johnstonianidae Thor, 1935 | | 1 | Species | Taxom |
| Karschiidae Walter, 1889 | | 7 | Species | Taxom |
| Knemidokoptidae (Lavoipierre ..., 1951) | | 2 | Species | Taxom |
| Laelapidae Berlese, 1892 | | 144 | Species | Taxom |
| Laminosioptidae Vitzthum, 1931 | | 1 | Species | Taxom |
| Lardoglyphidae Oudemans, 1927 | | 2 | Species | Taxom |
| Lebertiidae Thor, 1900 | | 7 | Species | Taxom |
| Leeuwenhoekiidae Womersley, 1944 | Chigger mites | 23 | Species | Taxom |
| Leptonetidae Simon, 1890 | Cave spiders | 171 | Species | Taxom |
| Liacaridae Sellnick, 1928 | | 8 | Species | Taxom |
| Liebstadiidae J. & P. Balogh, 1984 | | 1 | Species | Taxom |
| Limnesiidae Thor, 1900 | | 11 | Species | Taxom |
| Linyphiidae Blackwall, 1859 | Dwarf spiders | 781 | Species | Taxom |
| Liocranidae Simon, 1897 | Liocranid sac spiders | 45 | Species | Taxom |
| Liphistiidae Thorell, 1869 | Primitive burrowing spiders | 101 | Species | Taxom |
| Listrophoridae Mégnin & Tro..., 1884 | | 4 | Species | Taxom |
| Lohmanniidae Berlese, 1916 | | 17 | Species | Taxom |
| Lycosidae Lehtinen & H..., 1979 | Ground Spiders | 434 | Species | Taxom |
| Lyroppiidae Balogh, 1983 | | 1 | Species | Taxom |
| Machadobelbidae Balogh, 1972 | | 1 | Species | Taxom |
| Macrochelidae Vitzthum, 1930 | | 24 | Species | Taxom |
| Macronyssidae Oudemans, 1936 | Macronyssid Mites | 21 | Species | Taxom |
| Macrothelidae Simon, 1892 | | 27 | Species | Taxom |
| Malaconothridae Berlese, 1916 | | 12 | Species | Taxom |
| Melicharidae (Hirschmann, 1962) | | 4 | Species | Taxom |
| Mesoplophoridae Ewing, 1917 | | 3 | Species | Taxom |
| Metagynuridae Baker & Wharton, 1952 | | 1 | Species | Taxom |
| Microdispidae Cross, 1965 | | 1 | Species | Taxom |
| Microtegeidae Balogh, 1972 | | 2 | Species | Taxom |
| Microzetidae Grandjean, 1936 | | 2 | Species | Taxom |
| Micryphantidae (Bertkau, 1872) | | 2 | Species | Taxom |
| Mideopsidae Koenike, 1910 | | 1 | Species | Taxom |
| Mimetidae Simon, 1881 | Pirate spider | 32 | Species | Taxom |
| Miturgidae Simon, 1885 | Long-legged sac spiders | 68 | Species | Taxom |
| Mochlozetidae Grandjean, 1960 | | 9 | Species | Taxom |
| Mongolarachnidae Selden, Shih..., 2013 | | 1 | Species | Taxom |
| Mycobatidae Grandjean, 1954 | | 3 | Species | Taxom |
| Myobiidae Megnin, 1877 | | 9 | Species | Taxom |
| Myocoptidae Gunther, 1942 | | 1 | Species | Taxom |
| Mysmenidae Petrunkevitch, 1928 | Dwarf cobweb spiders | 77 | Species | Taxom |
| Nanhermanniidae Sellnick, 1928 | | 5 | Species | Taxom |
| Nemastomatidae Simon, 1872 | | 7 | Species | Taxom |
| Nemesiidae Simon, 1892 | Tube Trapdoor Spiders | 6 | Species | Taxom |
| Nenteriidae Hirschmann, 1979 | | 2 | Species | Taxom |
| Neobisiidae Chamberlin, 1930 | | 35 | Species | Taxom |
| Neoliodidae (Sellnick, 1928) | | 1 | Species | Taxom |
| Neopygmephoridae Cross, 1965 | | 7 | Species | Taxom |
| Neothrombiidae Feider, 1959 | | 1 | Species | Taxom |
| Nesticidae Simon, 1894 | Cave cobweb spider | 78 | Species | Taxom |
| Niphocepheidae Travé, 1959 | | 1 | Species | Taxom |
| Nippobodidae Aoki, 1959 | | 1 | Species | Taxom |
| Nosybeidae Mahunka, 1993 | | 1 | Species | Taxom |
| Nosybelbidae Mahunka, 1994 | | 6 | Species | Taxom |
| Nothridae Berlese, 1896 | | 6 | Species | Taxom |
| Ochyroceratidae Fage, 1912 | Midget ground weaver | 57 | Species | Taxom |
| Oecobiidae Blackwall, 1862 | Disc web spider | 13 | Species | Taxom |
| Ologamasidae Ryke, 1962 | | 29 | Species | Taxom |
| Olpiidae Banks, 1895 | | 2 | Species | Taxom |
| Oonopidae Simon, 1890 | Dwarf Cell Spiders | 153 | Species | Taxom |
| Oppiidae Sellnick, 1937 | | 45 | Species | Taxom |
| Oribatellidae Jacot, 1925 | | 2 | Species | Taxom |
| Oribatulidae Thor, 1929 | | 17 | Species | Taxom |
| Oribellidae (Kunst, 1971) | | 1 | Species | Taxom |
| Oribotritiidae Grandjean, 1954 | | 2 | Species | Taxom |
| Oripodidae Jacot, 1925 | | 1 | Species | Taxom |
| Otocepheidae Balogh, 1961 | | 27 | Species | Taxom |
| Otopheidomenidae Treat, 1955 | | 1 | Species | Taxom |
| Oxidae Viets, 1926 | | 1 | Species | Taxom |
| Oxyameridae Aoki, 1965 | | 1 | Species | Taxom |
| Oxyopidae Thorell, 1870 | Lynx spiders | 66 | Species | Taxom |
| Pachylaelapidae Berlese, 1913 | | 23 | Species | Taxom |
| Palpimanidae Thorell, 1870 | Palp-footed spiders | 5 | Species | Taxom |
| Parakalummidae Grandjean, 1936 | | 7 | Species | Taxom |
| Parasitidae Oudemans, 1901 | Beetle Mites | 106 | Species | Taxom |
| Parholaspididae Evans, 1956 | | 39 | Species | Taxom |
| Passalozetidae Grandjean, 1954 | | 1 | Species | Taxom |
| Pediculochelidae Lavoipierre, 1946 | | 3 | Species | Taxom |
| Petrobunidae Sharma & Gir..., 2011 | | 2 | Species | Taxom |
| Phalangiidae Latreille, 1802 | Daddy-Long-Legs | 38 | Species | Taxom |
| Phenopelopidae Petrunkevitch, 1955 | | 3 | Species | Taxom |
| Pheroliodidae Paschoal, 1987 | | 1 | Species | Taxom |
| Philodromidae Thorell, 1870 | False crab spiders | 81 | Species | Taxom |
| Pholcidae C. L. Koch, 1851 | Carpenter spider | 355 | Species | Taxom |
| Phrurolithidae Banks, 1892 | Phrurolithid Spiders | 116 | Species | Taxom |
| Phthiracaridae Perty, 1841 | | 19 | Species | Taxom |
| Phytoptidae Manson, 1970 | | 16 | Species | Taxom |
| Phytoseiidae Berlese, 1916 | Phytoseiid mites | 93 | Species | Taxom |
| Pimoidae Wunderlich, 1986 | Pimoid spiders | 64 | Species | Taxom |
| Pionidae Thor, 1900 | | 13 | Species | Taxom |
| Pisauridae Simon, 1890 | Big wolf spider | 49 | Species | Taxom |
| Plateremaeidae Trägårdh, 1931 | | 2 | Species | Taxom |
| Plectreuridae Simon, 1893 | Plectreurid spider | 1 | Species | Taxom |
| Pneumocoptidae Fain, 1957 | | 0 | Species | Taxom |
| Podapolipidae Husband, 1990 | | 4 | Species | Taxom |
| Podocinidae Berlese, 1913 | | 7 | Species | Taxom |
| Podoctidae Roewer, 1912 | | 4 | Species | Taxom |
| Poliocheridae Scudder, 1884 | | 1 | Species | Taxom |
| Polyaspididae Berlese, 1913 | | 2 | Species | Taxom |
| Pontarachnidae Koenike, 1910 | | 1 | Species | Taxom |
| Protoribatidae J. & P. Balogh, 1984 | | 10 | Species | Taxom |
| Psechridae James, 1989 | Psechrid spiders | 33 | Species | Taxom |
| Psilodercidae Machado, 1951 | | 9 | Species | Taxom |
| Psorergatidae Womersley, 1941 | | 1 | Species | Taxom |
| Psoroptidae Hering, 1838 | Scab mites | 7 | Species | Taxom |
| Pterolichidae Trouessart, 1899 | | 6 | Species | Taxom |
| Pteronyssidae Oudemans, 1941 | | 2 | Species | Taxom |
| Ptiloxenidae Gaud, 1982 | | 1 | Species | Taxom |
| Punctoribatidae Thor, 1937 | | 2 | Species | Taxom |
| Pygmephoridae Krczal, 1964 | | 1 | Species | Taxom |
| Pyroglyphidae Cunliffe, 1958 | Dust mites | 7 | Species | Taxom |
| Quadroppiidae Balogh, 1983 | | 1 | Species | Taxom |
| Raphignathidae Kramer, 1877 | | 6 | Species | Taxom |
| Rhinonyssidae Trouessart, 1895 | | 3 | Species | Taxom |
| Rhodacaridae Oudemans, 1902 | | 5 | Species | Taxom |
| Ricinoididae Ewing, 1929 | Hooded tickspiders | 1 | Species | Taxom |
| Sabaconidae Dresco, 1970 | Sabaconid Harvestmen | 5 | Species | Taxom |
| Salticidae Blackwall, 1842 | Jumping Spider | 1006 | Species | Taxom |
| Sandokanidae Özdikmen & K..., 2007 | | 1 | Species | Taxom |
| Sarcoptidae Megnin, 1877 | Itch mites | 13 | Species | Taxom |
| Scheloribatidae Jacot, 1935 | | 15 | Species | Taxom |
| Sclerosomatidae Simon, 1879 | Sclerosomatid Harvestmen | 68 | Species | Taxom |
| Scorpionidae Pierre André..., 1802 | Largeclaw scorpions | 5 | Species | Taxom |
| Scutacaridae Paoli, 1911 | | 7 | Species | Taxom |
| Scutoverticidae Grandjean, 1954 | | 1 | Species | Taxom |
| Scytodidae Blackwall, 1864 | Glue spitter | 24 | Species | Taxom |
| Segestriidae Simon, 1893 | Six-eyed Spiders | 15 | Species | Taxom |
| Sejidae Berlese, 1885 | | 1 | Species | Taxom |
| Selenopidae Simon, 1897 | Flatties | 11 | Species | Taxom |
| Selenoribatidae Schuster, 1963 | | 1 | Species | Taxom |
| Sicariidae Keyserling, 1880 | Brown recluse spiders | 3 | Species | Taxom |
| Sinopimoidae Li & Wunderlich, 2008 | | 1 | Species | Taxom |
| Siteroptidae Martin, 1978 | Siteroptid mites | 6 | Species | Taxom |
| Sparassidae Bertkau, 1872 | Giant crab spiders | 311 | Species | Taxom |
| Sperchontidae Thor, 1900 | | 9 | Species | Taxom |
| Spinozetidae Balogh, 1972 | | 1 | Species | Taxom |
| Spinturnicidae Oudemans, 1902 | | 9 | Species | Taxom |
| Steganacaridae (Niedbała, 1986) | | 4 | Species | Taxom |
| Stenochilidae Thorell, 1873 | Stenochilid spiders | 1 | Species | Taxom |
| Stigmaeidae Wood, 1967 | | 64 | Species | Taxom |
| Suctobelbidae Jacot, 1938 | | 15 | Species | Taxom |
| Suidasiidae Hughes, 1948 | | 3 | Species | Taxom |
| Syarinidae Chamberlin, 1930 | | 1 | Species | Taxom |
| Symphytognathidae Hickman, 1931 | Dwarf orb-weavers | 43 | Species | Taxom |
| Synichotritiidae Walker, 1965 | | 3 | Species | Taxom |
| Syringobiidae Trouessart, 1897 | | 1 | Species | Taxom |
| Syringophilidae Lavoipierre, 1953 | Quill mites | 11 | Species | Taxom |
| Tanaupodidae Thor, 1935 | | 2 | Species | Taxom |
| Tarsonemidae Kramer, 1877 | Tarsonemid mites | 72 | Species | Taxom |
| Tectocepheidae Grandjean, 1954 | | 3 | Species | Taxom |
| Tegeocranellidae P. Balogh, 1987 | | 1 | Species | Taxom |
| Tegoribatidae Grandjean, 1954 | | 2 | Species | Taxom |
| Telemidae Fage, 1913 | Long-legged cave spider | 82 | Species | Taxom |
| Tenuialidae Jacot, 1929 | | 1 | Species | Taxom |
| Tenuipalpidae Berlese, 1913 | False spider mites | 57 | Species | Taxom |
| Tetrablemmidae O. P-Cambridge, 1873 | Armored spider | 31 | Species | Taxom |
| Tetragnathidae Menge, 1866 | Elongated Orb Weavers | 211 | Species | Taxom |
| Tetranychidae Donnadieu, 1875 | Spider mites | 260 | Species | Taxom |
| Thelyphonidae Lucas, 1835 | | 11 | Species | Taxom |
| Theraphosidae Thorell, 1870 | Bird-eating spiders | 30 | Species | Taxom |
| Theridiidae Sundevall, 1833 | Cobweb And Widow Spiders | 547 | Species | Taxom |
| Theridiosomatidae Simon, 1881 | Ray orbweavers | 39 | Species | Taxom |
| Thomisidae Sundevall, 1833 | Crab Spider | 415 | Species | Taxom |
| Thyrisomidae Grandjean, 1953 | | 3 | Species | Taxom |
| Titanoecidae Lehtinen, 1967 | Rock Weavers | 14 | Species | Taxom |
| Torrenticolidae Thor, 1902 | Torrent Mites | 9 | Species | Taxom |
| Trachelidae Simon, 1897 | | 3 | Species | Taxom |
| Trachyuropodidae Kramer, 1881 | | 2 | Species | Taxom |
| Trechaleidae Simon, 1890 | Trechaleid spiders | 3 | Species | Taxom |
| Trematuridae Berlese, 1917 | | 6 | Species | Taxom |
| Trhypochthoniidae Willmann, 1931 | | 7 | Species | Taxom |
| Trochanteriidae Karsch, 1879 | Flat spiders | 13 | Species | Taxom |
| Trogulidae Sundevall, 1833 | | 2 | Species | Taxom |
| Trombiculidae Ewing, 1929 | Chigger mites | 334 | Species | Taxom |
| Trombidiidae Leach, 1815 | Beer Bahuti | 4 | Species | Taxom |
| Tuckerellidae Baker & Prit..., 1953 | Peacock mites | 5 | Species | Taxom |
| Tydeidae Kramer, 1877 | Tydeid mites | 5 | Species | Taxom |
| Uloboridae Thorell, 1869 | Cribellate orb weavers | 56 | Species | Taxom |
| Unionicolidae Oudemans, 1909 | | 23 | Species | Taxom |
| Urodinychidae Berlese, 1917 | | 6 | Species | Taxom |
| Uropodellidae (Camin, 1955) | | 1 | Species | Taxom |
| Uropodidae Kramer, 1881 | | 4 | Species | Taxom |
| Varroidae Delfinado & ..., 1974 | | 3 | Species | Taxom |
| Veigaiidae Oudemans, 1939 | | 21 | Species | Taxom |
| Walchiidae Ewing, 1946 | | 1 | Species | Taxom |
| Winterschmidtiidae Oudemans, 1923 | | 1 | Species | Taxom |
| Withiidae Chamberlin, 1931 | | 4 | Species | Taxom |
| Xenillidae Woolley & Hi..., 1966 | | 2 | Species | Taxom |
| Xenocaligonellididae González, 1978 | | 2 | Species | Taxom |
| Zerconidae Berlese, 1892 | | 34 | Species | Taxom |
| Zetomotrichidae Grandjean, 1934 | | 1 | Species | Taxom |
| Zetorchestidae Michael, 1898 | | 2 | Species | Taxom |
| Zodariidae Thorell, 1881 | Ant spiders | 79 | Species | Taxom |
| Zoridae F. O. P-Camb..., 1893 | Wandering Spiders | 4 | Species | Taxom |
| Zoropsidae Bertkau, 1882 | False Huntsman Spiders | 7 | Species | Taxom |