- Labeobarbus Rüppell 1835
- Labia Leach 1915
- Labiobulura Skrjabin & Schikhobalova 1948
- Labracoglossa Peters 1866
- Labroides Bleeker 1851
- Lacazella Munier-Chalmas 1880
- Laccobius Erichson 1837
- Laccophilus Leach 1815
- Laccotrephes Stål 1866
- Lachnocrepis LeConte 1853
- Lachnolebia Maindron 1905
- Lactoria Jordan & Fowler 1902
- Lactuca Linné
- Lacuna Turton 1827
- Laelaps Koch 1836
- Laemobothrion Nitzsch 1818
- Laemodonta Philippi 1846
- Laeops Günther 1880
- Laetmaster Fisher 1908
- Laevapex Walker 1903
- Lagenammina Rhumbler 1911
- Lagenodelphis Fraser 1957
- Lagis Malmgren 1866
- Lagocephalus Swainson 1839
- Lagonis Ross 1937
- Laguncula Benson 1842
- Lagurus Gloger 1841
- Lampea Stechow 1921
- Lampetra Bonnaterre 1788
- Lamprops G.O. Sars 1863
- Lamprotornis Temminck 1820
- Lanius Linnaeus 1758
- Laodicea Lesson 1843
- Laqueus Dall 1870
- Larvivora Hodgson 1837
- Lasaea Brown 1827
- Lasianthus William Jack 1823
- Lasioglossum Curtis 1833
- Lasius Fabricius 1804
- Lataxiphyda Smith 2008
- Lateolabrax Bleeker 1855
- Laternula Röding 1798
- Lates G. Cuvier 1828
- Latirulus Cossmann 1889
- Latropiscis Whitley 1931
- Laurencia J.V. Lamouroux 1813
- Lauriea Baba 1971
- Leathesia S.F. Gray 1821
- Lebbeus White 1847
- Lebia Latreille 1802
- Lebidia A. Morawitz 1862
- Lecane Nitzsch 1827
- Ledum
- Lefua Herzenstein 1888
- Leiaster Peters 1852
- Leiodytes Guignot 1936
- Leiognathus Lacépède 1802
- Leiothrix Swainson 1832
- Leipsuropus Stebbing 1899
- Leishmania Ross 1903
- Leistus Frölich 1799
- Leodice Lamarck 1818
- Lepadella Bory de St. Vincent 1826
- Lepeophtheirus von Nordmann 1832
- Lepidonotus Leach 1816
- Lepidotrigla Günther 1860
- Lepidozona Pilsbry 1892
- Lepisosteus Linnaeus 1758
- Lepocinclis Perty 1849
- Lepomis Rafinesque 1819
- Leptanilla Emery 1870
- Leptaulopus Gomon, Struthers & Stewart 2013
- Leptobotia Bleeker 1870
- Leptocarabus Gehin 1885
- Leptochelia Dana 1849
- Leptocimbex Semenov 1896
- Leptocorisa Latreille 1829
- Leptogenys Roger 1861
- Leptolecithum Kobayashi 1915
- Leptoseris Milne-Edwards & Haime 1849
- Leptostylis G.O. Sars 1869
- Leptothorax Mayr 1855
- Leptychaster E.A. Smith 1876
- Lepus Linnaeus 1758
- Lernaea Linnaeus 1758
- Lernaeenicus Le Sueur 1824
- Lernanthropinus Do 1985
- Lernanthropsis Do 1985
- Lernanthropus de Blainville 1822
- Lespedeza
- Lestes Leach 1815
- Lesticus Dejean 1828
- Lethenteron Creaser & Carl Hubbs 1922
- Lethocerus Mayr 1853
- Lethotremus Gilbert 1896
- Lethrinus Cuvier 1829
- Leuckartiara Hartlaub 1914
- Leucon Krøyer 1846
- Leucophenga Mik 1866
- Leucosceptrum
- Leucopsarion Hilgendorf 1880
- Leucothea Mertens 1833
- Levinebalia Walker-Smith 2000
- Lianoe Gozis 1882
- Lichomolgus Thorell 1859
- Ligia Fabricius 1798
- Ligula Bloch 1782
- Ligustrum Linné
- Lilium Linné
- Limnaea
- Limnocarabus Gehin 1876
- Limnocletodes Borutsky 1926
- Limnoithona Burckhardt 1913
- Limnoncaea Kokubo 1914
- Limnoperna Rochebrune 1882
- Limosella Linné
- Limnotrachelobdella Epshtein 1968
- Limulus O.F. Müller 1785
- Linckia Nardo 1834
- Linepithema Mayr 1866
- Lineus Sowerby 1806
- Lingula Bruguière 1791
- Linuche Eschscholtz 1829
- Liobagrus Hilgendorf 1878
- Liodrosophila Duda 1922
- Liolophura Pilsbry 1893
- Liomyrmex Mayr 1865
- Liophilydrodes Nakane & Sawada
- Lioptera Chaudoir 1869
- Lioscorpius Günther 1880
- Liothyrella Thomson 1916
- Liparis Scopoli 1777
- Lipoptena Nitzsch 1818
- Liriope Lesson 1843
- Lischkeia P. Fischer 1879
- Lithobates Fitzinger 1843
- Lithocarpus Blume
- Lithodes Latreille 1806
- Lithosoma Fisher 1911
- Litomosa Yorke & Maplestone 1926
- Litomosoides Chandler 1931
- Litopenaeus Pérez Farfante 1969
- Lithotrya Sowerby 1822
- Litsea Lamarck 1789
- Littoraria Griffith & Pidgeon 1834
- Livistona Robert Brown
- Livoneca Leach 1818
- Lobatolampea Horita 2000
- Loboharpalus Schauberger 1932
- Lobrathium Mulsant & Rey 1878
- Locustogammarus Bousfield 1979
- Loimia Malmgren 1866
- Lonchura Sykes 1832
- Longistriata Schulz 1926
- Lophaster Verrill 1878
- Lophiomus Gill 1883
- Lophogaster M. Sars 1857
- Lordiphosa Basden 1961
- Lordomyrma Emery 1897
- Lorica H. Adams & A. Adams 1852
- Losaria Moore 1902
- Lotongus Distant 1886
- Lottia Gray 1833
- Loxodonta Anonymous 1827
- Lucensosergia Vereshchaka Olesen & Lunina 2014
- Luchuconulus Pilsbry 1928
- Luchuena Habe 1956
- Luchuhadra Kuroda & Habe 1949
- Luchuphaedusa Pilsbry 1901
- Lucidina Gorham 1883
- Lucilina Dall 1882
- Luciogobius Gill 1859
- Luciola Laporte 1833
- Luehdorfia Crüger 1878
- Luidia Forbes 1839
- Lumbricus Linnaeus 1758
- Lumnitzera Willdenow 1803
- Lunella Röding 1798
- Luscinia T. Forster 1817
- Lutjanus Bloch 1790
- Lutra Brünnich 1771
- Lygocoris Reuter 1875
- Lymnaea Lamarck 1799
- Lyrocteis Komai 1941
- Lyrothorax Chaudor 1838
- Lysidice Savigny 1818
- Lysilla Malmgren 1866