- Sabellastarte Krøyer 1856
- Saccella Woodring 1925
- Saccharum Linné
- Saccostrea Dollfus & Dautzenberg 1920
- Sacura Jordan & Richardson 1910
- Sadonebria Ledoux & Roux 2005
- Sagamia D.S. Jordan & Snyder 1901
- Sagarmathametopus Yasunaga & Duwal 2006
- Sagitta Quoy & Gaimard 1827
- Sagum Wilson 1913
- Salamandrella Dybowski 1870
- Salangichthys Bleeker 1860
- Salarias G. Cuvier 1816
- Salix Linné
- Salmaciella Mortensen 1942
- Salmincola Wilson 1915
- Salmo Linnaeus 1758
- Saloptia Smith 1964
- Salpingotus Vinogradov 1922
- Salvatoria McIntosh 1885
- Salvelinema Trofimenko 1962
- Salvelinus J. Richardson 1836
- Sambucus Linné
- Sander Oken 1817
- Sarasaeschna Karube & Yeh 2001
- Sarcocheilichthys Bleeker 1860
- Sarconema Wehr 1939
- Sarcophilus F.G. Cuvier 1837
- Sarcotaces Olsson 1872
- Sarda Cuvier 1829
- Sardinella Valenciennes
- Sardinops Hubbs 1929
- Sargassum C. Agardh 1820
- Sargocentron Fowler 1904
- Sarotherodon Rüppell 1852
- Sarsia Lesson 1843
- Sasa Makino & Shibata
- Sasamorpha
- Satsuma Adams 1868
- Satyrichthys Kaup 1873
- Saurida Valenciennes 1850
- Savignium Leach 1825
- Scabiosa
- Scaevola Linné
- Scalibregma Rathke 1843
- Scaliola A. Adams 1860
- Scalpellum Leach 1818
- Scapharca Gray 1847
- Scaphechinus A. Agassiz 1863
- Scaphirhynchus Heckel 1835
- Scaptodrosophila Duda 1923
- Scaptomyza Hardy 1849
- Scarites Fabricius 1775
- Scartelaos Swainson 1839
- Scartella D.S. Jordan 1886
- Scarus Forsskål 1775
- Scatophagus Cuvier 1831
- Scepticus Roelofs 1873
- Schefflera J.R.Forster & G.Forster 1775
- Schima Reinw. ex Blume (1823)
- Schistocerca Stål 1873
- Schistosoma Weinland 1858
- Schizaster L. Agassiz 1836
- Schizophragma Siebold & Zucc.
- Sciaena Linnaeus 1758
- Scirpus Linné
- Sciurus Linnaeus 1758
- Sclerasterias Perrier 1891
- Sclerocrangon Sars 1883
- Scoletoma Blainville 1828 emended Frame 1992
- Scoliodon J.P. Müller & Henle 1838
- Scolopax Linnaeus 1758
- Scolopsis Cuvier 1814
- Scomber Linnaeus 1758
- Scomberomorus Lacépède 1801
- Scombrops Temminck & Schlegel 1845
- Scorpaena Linnaeus 1758
- Scorpaenodes Bleeker 1857
- Scorpaenopsis Heckel 1840
- Scyliorhinus Blainville 1816
- Scylla De Haan 1833
- Scyllarides Gill 1898
- Scyphoproctus Gravier 1904
- Scytosiphon C. Agardh 1820
- Sebastes Cuvier 1829
- Sebastichthys Gill 1862
- Sebastiscus Jordan & Starks 1904
- Sebastolobus Gill 1881
- Secutor Gistel 1848
- Segmentina Fleming 1818
- Selar Bleeker 1851
- Semiarundinaria
- Semibalanus Pilsbry 1916
- Semicossyphus Günther 1861
- Semiricinula Martens 1904
- Semisulcospira Boettger 1886
- Septaria Férussac 1807
- Septifer Récluz 1848
- Serendiba Distant 1906
- Sergia Stimpson 1860
- Seriaster Jangoux 1984
- Serinus Koch 1816
- Seriola Cuvier 1816
- Serpinema Yeh 1960
- Serpula Linnaeus 1758
- Serratosagitta Tokioka 1965
- Serratospiculum Skrjabin 1915
- Sertularia Linnaeus 1758
- Sesarma Say 1817
- Sesarmoides Serène & Soh 1970
- Sesarmops Serène & Soh 1970
- Sesuvium Linné
- Setaria Viborg 1795 [Nematoda]
- Setaria P. Beauv. 1812 [Tracheophyta]
- Setodes Rambur 1842
- Seuratia Skrjabin 1916
- Seuratum Hall 1916
- Seurocyrnea Strand 1929
- Shigella Castellani & Chalmers 1919
- Shiracidia Ito 1984
- Shorea Kurz
- Sicista Gray 1827
- Sicyopterus T.N. Gill 1860
- Sievelsia
- Siganus Forsskål 1775
- Sigara Fabricius 1775
- Sige Malmgren 1865
- Silhouettea J.L.B. Smith 1959
- Sillago Cuvier 1816
- Silpha Linnaeus 1758
- Silurus Linnaeus 1758
- Simplicithyris Zezina 1976
- Simplisetia Hartmann-Schröder 1985
- Sinanodonta Modell 1945
- Sinicephus Maa 1949
- Sinictinogomphus Fraser 1939
- Sinodiaptomus Kiefer 1932
- Sinoennea Kobelt 1904
- Sinonychus Jéich & Boukal 1995
- Sinorchestia Miyamoto & Morino 1999
- Sinotaia Haas 1939
- Siobla Cameron 1877
- Sipalinus Marshall 1943
- Siphonalia A. Adams 1863
- Siphonaria G.B. Sowerby I 1823
- Siren Linnaeus 1766
- Siriella Dana 1850
- Sitalina Thiele 1931
- Skeletonema Greville 1865
- Skrjabingylus Petrov 1927
- Smenispa Özdikem 2009
- Smilium Leach 1825
- Soboliphyme Petrov 1930
- Sogda Lopatin 1961
- Solaster Forbes 1839
- Solen Linnaeus 1758
- Solenomphala Martens 1883
- Solenopotes Enderlein 1904
- Solenopsis Westwood 1840
- Solidago Linné
- Somatochlora Sélys 1871
- Sonchus Linné
- Sorbus
- Sorex Linnaeus 1758
- Soriculus Blyth 1854
- SouthwellinaWitenberg 1932
- Sparganium Linné
- Sparus Linnaeus 1758
- Spasskogammarus Bousfield 1979
- Spermophilus Cuvier 1825
- Sphaerium Scopoli 1777
- Sphaerosyllis Claparède 1863
- Sphaerotrichia Kylin 1940
- Sphagnum Linné
- Sphoeroides Anonymous 1798
- Sphyraena Klein 1778
- Sphyrna Rafinesque 1810
- Spiculopteragia Orloff 1933
- Spilornis G.R. Gray 1840
- Spinitectus Fourment 1883
- Spinther Johnston 1845
- Spiraea
- Spirobranchus Blainville 1818
- Spirocerca Railliet & Henry 1911
- Spirofilaria Yamaguti 1935
- Spirogyra Link in C. G. Nees
- Spirometra
- Spirorbis Daudin 1800
- Spirostoma Heude 1885
- Spiroxys Schneider 1866
- Spirura Blanchard 1849
- Spizaetus Vieillot 1816
- Spongovostox Burr 1911
- Spratelloides Bleeker 1851
- Springerichthys Shen 1994
- Squalidus Dybowski 1872
- Squalus Linnaeus 1758
- Squatina Duméril 1806
- Stachyurus Siebold & Zuccarini
- Staphylea Linné
- Stefanskostrongylus Drozdz 1970
- Stegana Meigen 1830
- Stegophorus Wehr 1934
- Stegostoma Müller & Henle 1837
- Stellantchasmus Onji & Nishio 1916
- Stemonosudis Harry 1951
- Stenalpheops Miya 1997
- Stenella Gray 1866
- Stenocephus Shinohara 1999
- Stenodynerus Saussure 1863
- Stenogobiops Polunin & Lubbock 1977
- Stenolophus Dejean 1821
- Stenomelania Fischer 1885
- Stenoplax Dall 1879
- Stenopsyche McLachlan 1866
- Stenothyra Benson 1856
- Stenurus Dujardin 1845
- Stephanocyathus Seguenza 1864
- Stephanofilaria Ihle & Ihle-Landenberg 1933
- Stephanolepis T. N. Gill 1861
- Stephanophyllia Michelin 1841
- Stephanoprora Odhner 1902
- Stephanurus Diesing 1839
- Stereocidaris Pomel 1883
- Stereomastis Bate 1888
- Stereophaedusa O. Boettger 1877
- Stereozaptyx Pilsbry 1905
- Stereus Wollaston 1857
- Sternaspis Otto 1821
- Sternolophus Solier 1834
- Sternomoera Barnard & Karaman 1982
- Stethojulis Günther 1861
- Stethomostus Benson 1939
- Stethothyris Thomson 1918
- Sthenelais Kinberg 1855
- Stibarobdella Leigh-Sharpe 1925
- Stichaeopsis Kner in Steindachner & Kner 1870
- Stichopus Brandt 1835
- Stigmatomma Roger 1859
- Stilifer Broderip 1832
- Stiphodon M.C.W. Weber 1895
- Stirocorsia Konow 1897
- Stizostedion Rafinesque 1820
- Stlengis Jordan & Starks 1904
- Stolephorus Lacepède 1803
- Stomis Clairville 1806
- Stonogobiops Polunin & Lubbock 1977
- Streblosoma Sars 1872
- Streptocara Railliet Henry & Sisoff 1912
- Streptopelia Bonaparte 1855
- Streptopharagus Blanc 1912
- Strigatella Swainson 1840
- Strix Linnaeus 1758
- Strombus Linnaeus 1758
- Strongygaster Macquart 1834
- Strongylacantha van Beneden 1873
- Strongylocentrotus Brandt 1835
- Strongyloides Grassi 1879
- Strongylura van Hasselt 1824
- Strongylus Müller 1780
- Strumigenys F. Smith 1860
- Styela Fleming 1822
- Stylaster Gray 1831
- Stylifer Cossmann 1921
- Stylochus Ehrenberg 1831
- Stylocoeniella Yabe & Sugiyama 1935
- Stylodipus G.M. Allen 1925
- Styrax Linné
- Suberites Nardo 1833
- Subulura Molin 1860
- Suezichthys Smith 1958
- Suggrundus Whitley 1930
- Suncus Ehrenberg 1832
- Supplanaxis Thiele 1929
- Surugathyris Yabe & Hatai 1934
- Sus Linnaeus 1758
- Suzuka S. Uéno 1956
- Sycon Risso 1826
- Syllis Savigny 1818
- Sympetrum Newman 1833
- Symplocos N.J. von Jacquin
- Synchiropus Gill 1859
- Synergus Hartig 1840
- Syngamus Siebold 1836
- Syngnathoides Bleeker 1851
- Syngnathus Linnaeus 1758
- Synhimantus Railliet, Henry & Sisoff 1916
- Synodus Scopoli 1777
- Synuchus Gyllenhal 1810
- Syphacia Seurat 1916
- Sypharista Quentin 1971
- Syrista Konow 1896
- Syrmaticus Wagler 1832