• Tetrada Neckaja, 1958 †
• Tetradactylus Merrem, 1820
• Tetradactylus africanus Gray, 1838
• Tetradactylus bilineatus Hewitt, 1926 accepted as Tetradactylus tetradactylus Daudin, 1802
• Tetradactylus boulengeri de Witte, 1933 accepted as Tetradactylus ellenbergeri Angel, 1922
• Tetradactylus breyeri Roux, 1907
• Tetradactylus chalcidicus Merrem, 1820 accepted as Tetradactylus tetradactylus Daudin, 1802
• Tetradactylus decresiensis Cuvier, 1829 accepted as Hemiergis peronii Gray, 1831
• Tetradactylus eastwoodae Hewitt & Methuen, 1913
• Tetradactylus ellenbergeri Angel, 1922
• Tetradactylus fitzsimonsi Hewitt, 1915 accepted as Tetradactylus africanus Gray, 1838
• Tetradactylus guttulatus Macleay, 1885 (uncertain > taxon inquirendum)
• Tetradactylus laevicauda Hewitt, 1915 accepted as Tetradactylus seps Linnaeus, 1758
• Tetradactylus lundensis Monard, 1937 accepted as Tetradactylus ellenbergeri Angel, 1922
• Tetradactylus seps Linnaeus, 1758
• Tetradactylus tetradactylus Daudin, 1802
• Tetradactylus udzungwensis Salvidio, Menegon, Sindaco & Moyer, 2004
• Tetradacus Miyake, 1919 (uncertain)
• Tetradapa P. Osbeck, 1757 accepted as Erythrina Linnaeus, 1753
• Tetradapa javanorum Osbeck accepted as Erythrina variegata Linnaeus
• Tetradeion Stebbing, 1899
• Tetradeion angustipalma (Berge & Vader, 2000)
• Tetradeion angustipalpa (Berge & Vader, 2000)
• Tetradeion crassum (Chilton, 1883)
• Tetradeion dampieri (Berge & Vader, 2000)
• Tetradeion latum (Haswell, 1879)
• Tetradeion latus (Haswell, 1879)
• Tetradeion quatro Berge & Vader, 2000
• Tetradella Ulrich, 1890 †
• Tetradellidae Swartz, 1936 †
• Tetradellina Harris, 1957 † (uncertain)
• Tetradelphynema Schulz, 1927 accepted as Physaloptera Rudolphi, 1819
• Tetradelphynema tumefaciens Henry & Blanc
• Tetradelus Fauvel, 1904
• Tetradema Schlechter, 1920 accepted as Agalmyla Blume, 1826
• Tetradenia Bentham, 1830 [Family: Lamiaceae]
• Tetradenia C.G.D. Nees in Wallich, 1831 (unaccepted) [Family: Lauraceae]
• Tetradenos Linstow, 1904 accepted as Tanqua Blanchard, 1904
• Tetrades Bleeker, 1864 accepted as Dascyllus Cuvier, 1829
• Tetradesmus G.M. Smith, 1913
• Tetradesmus cumbricus G.S. West, 1915
• Tetradesmus lunatus Korshikov
• Tetradesmus maior (Fischer) Fott & Komárek, 1974
• Tetradesmus wisconsinensis G.M. Smith, 1913
• Tetradia Du Petit-Thouars ex Tulasne, 1856 (unaccepted) [Family: Lythraceae]
• Tetradia R. Brown, 1844 accepted as Pterygota H.W. Schott & Endlicher, 1832 [Family: Malvaceae]
• Tetradia T. Johnson, 1904 [Family: Ascomycota incertae sedis]
• Tetradia Thomson, 1864 [Family: Cerambycidae]
• Tetradia fasciatocollis Thomson, 1864 accepted as Tetradia lophoptera (Guérin-Méneville, 1844)
• Tetradia lophoptera (Guérin-Méneville, 1844)
• Tetradia monodi Lepesme, 1947 accepted as Tetradia lophoptera (Guérin-Méneville, 1844)
• Tetradiacrium Hort., 1986 (uncertain)
• Tetradiclidaceae Takhtajan, 1986 accepted as Nitrariaceae Lindley, 1830
• Tetradiclis Steven ex Marschall von Bieberstein, 1819-1820
• Tetradictyon M.A. Romanov, 1964 (uncertain)
• Tetradidemnum Della Valle, 1881 accepted as Didemnum Savigny, 1816
• Tetradidemnum albidum (Verrill, 1871) accepted as Didemnum albidum (Verrill, 1871)
• Tetradidemnum gigas Della Valle, 1881 accepted as Didemnum gigas (Della Valle, 1881)
• Tetradiella Liao & Lin, 1981 †
• Tetradigita R. Kar, B.D. Mandaokar & R.K. Kar, 2009 †
• Tetradiida †
• Tetradiidae †
• Tetradimorpha Hsiung, 1927
• Tetradimorpha marina Fenchel et al., 1995
• Tetradinium Klebs, 1912 [Phylum: Miozoa]
• Tetradinium Vavrdová, 1973 † accepted as Tetraniveum Vavrdová, 1976 † [Phylum: Acritarcha]
• Tetradinium chiastosporum Harris, 1939 accepted as Gymnodinium chiastosporum (T.M. Harris) Cridland, 1958
• Tetradinium intermedium Geitler, 1928
• Tetradinium javanicum Klebs, 1912
• Tetradinium minus Pascher
• Tetradinium minutum Sinha, Prasad & Srivastava, 1998 †
• Tetradinium simplex Prescott, 1949
• Tetradinodula Zha in Zha et al., 2017
• Tetradiplosis Kieffer, 1910
• Tetradiplosis sexdentatus Kieffer & Jorgensen, 1910
• Tetradiscalis Enderlein, 1928
• Tetradiscalis steinbachi Enderlein, 1928 accepted as Dexosarcophaga transita Townsend, 1917
• Tetradiscus Bigot, 1886 accepted as Chyliza Fallén, 1820
• Tetradiscus notatus Bigot, 1886 accepted as Chyliza bigoti Melander, 1920
• Tetradiscus pictus Bigot, 1886 accepted as Chyliza apicalis Loew, 1860
• Tetradites I.C. Cookson, 1947 † (uncertain) [Phylum: Sporae dispersae]
• Tetradites Sokolov, 1950 † (unaccepted > nomen nudum) [Phylum: Cnidaria]
• Tetradites T. van der Hammen, 1954 † (unaccepted) [Phylum: Sporae dispersae]
• Tetraditrupa Regenhardt, 1961 † (uncertain)
• Tetraditryma Baumgartner, 1980 †
• Tetradium Dana in Wilkes, 1841 † [Family: Tetradiidae]
• Tetradium Dulac, 1867 accepted as Rhodiola Linnaeus, 1753 [Family: Crassulaceae]
• Tetradium Loureiro, 1790 [Family: Rutaceae]
• Tetradium Schlechtendal, 1852 accepted as Bremia Regel, 1843 [Family: Peronosporaceae]
• Tetradium Schmidt, 1874 † accepted as Palaenigma Walcott, 1885 † [Family: Conulariida (awaiting allocation)]
• Tetradium approximatum Ulrich †
• Tetradium cellulosum Hall †
• Tetradium conjugatum Hill, 1955 †
• Tetradium dendroides Hill, 1955 †
• Tetradium fibratum Safford †
• Tetradium minus Safford †
• Tetradium tasmaniense Chapman, 1919 †
• Tetradoa Pichon, 1947 accepted as Pleiocarpa Bentham in Bentham & J.D. Hooker, 1876
• Tetradomermis Rubtsov, 1967
• Tetradomermis angusta Rubtsov, 1967