Notonecta (from Ancient Greek νῶτον (nôton), meaning "back", and νηκτός (nēktós), meaning "swimmer"), known as backswimmers or water-boatmen, is a genus of aquatic insects in the bug family Notonectidae.

Species: These 70 species belong to the genus Notonecta:

• Notonecta amplifica Kiritshenko, 1931 (Europe, Asia)
• Notonecta arabiensis Hungerford, 1926 (Palearctic)
• Notonecta bicirca Hungerford, 1926 (South America)
• Notonecta bicircoidea Hungerford, 1928 (South America)
• Notonecta bifasciata Guérin-Méneville, 1844 (South America)
• Notonecta borealis Hussey, 1919 (North America)
• Notonecta canariensis Kirkaldy, 1897 (Africa)
• Notonecta ceres Kirkaldy, 1897 (Central America)
• Notonecta chinensis Fallou, 1887 (Southern Asia)
• Notonecta colombiana Hungerford, 1933 (South America)
• Notonecta compacta Hungerford, 1925 (Central America)
• Notonecta confusa Hungerford, 1930 (South America)
• Notonecta distinctoidea Hungerford, 1930 (Central America)
• Notonecta disturbata Hungerford, 1926 (South America)
• Notonecta fazi Hungerford, 1930 (South America)
• Notonecta glauca Linnaeus, 1758 (Africa, Palearctic)
• Notonecta handlirschi Kirkaldy, 1897 (Australia)
• Notonecta hintoni Hungerford, 1933 (Central America)
• Notonecta hoffmanni Hungerford, 1925 (Central and North America)
• Notonecta huincamoreni Bachmann, 1962 (South America)
• Notonecta hungerfordi J. Polhemus, 1993 (South America)
• Notonecta impressa Fieber, 1851 (Central America)
• Notonecta inca Mazzucconi, 2000 (South America)
• Notonecta indica Linnaeus, 1771 (the Americas, Oceania)
• Notonecta indicoidea Hungerford, 1927 (Central America)
• Notonecta insulata Kirby, 1837 (North America)
• Notonecta irrorata Uhler, 1879 (North America)
• Notonecta itatiaia Barbosa & Nessimian, 2013 (South America)
• Notonecta kiangsis Kirkaldy, 1902 (Europe, Asia)
• Notonecta kirbyi Hungerford, 1925 (North America)
• Notonecta kirkaldyi Martin, 1902 (Southern Asia)
• Notonecta lactitans Kirkaldy, 1897 (Africa)
• Notonecta lobata Hungerford, 1925 (Central and North America)
• Notonecta lunata Hungerford, 1926 (North America)
• Notonecta lutea Müller, 1776 (Palearctic)
• Notonecta maculata Fabricius, 1794 (Africa, Palearctic)
• Notonecta meinertzhageni Poisson, 1933 (Africa)
• Notonecta melaena Kirkaldy, 1897 (Central America)
• Notonecta meridionalis Poisson, 1926 (Africa, Palearctic)
• Notonecta mexicana Amyot & Serville, 1843 (the Americas)
• Notonecta montandoni Kirkaldy, 1897 (Southern Asia)
• Notonecta montezuma Kirkaldy, 1897 (Central and North America)
• Notonecta nigra Fieber, 1852 (South America)
• Notonecta obliqua Gallen, 1787 (Palearctic)
• Notonecta ochrothoe Kirkaldy, 1897 (South America)
• Notonecta pallidula Poisson, 1926 (Africa)
• Notonecta penecompacta Hungerford, 1938 (Central America)
• Notonecta penelobata Hungerford, 1938 (Central America)
• Notonecta peruviana Hungerford, 1933 (South America)
• Notonecta petrunkevitchi Hutchinson, 1945 (North America)
• Notonecta polystolisma Fieber, 1851 (South America)
• Notonecta pulchra Hungerford, 1926 (South America)
• Notonecta raleighi Torre-Bueno, 1907 (North America)
• Notonecta repanda Hungerford, 1933 (Central and North America)
• Notonecta reuteri Hungerford, 1928 (Europe and Asia)
• Notonecta robusta Hungerford, 1932 (Central America)
• Notonecta saramao Esaki, 1932 (Southern Asia)
• Notonecta sellata Fieber, 1851 (South America)
• Notonecta shooteri Uhler, 1894 (Central America and North America)
• Notonecta spinosa Hungerford, 1930 (North America)
• Notonecta thomasi Hungerford, 1937 (Central America)
• Notonecta triguttata Motschulsky, 1861 (Europe and Asia)
• Notonecta uhleri Kirkaldy, 1897 (North America)
• Notonecta undulata Say, 1832 (North America)
• Notonecta unifasciata Guérin-Méneville, 1857 (the Americas)
• Notonecta variabilis Fieber, 1852 (North America, South America)
• Notonecta vereertbruggheni Hungerford, 1928 (South America)
• Notonecta violacea Kirkaldy, 1897 (Southern Asia)
• Notonecta virescens Blanchard, 1852 (South America)
• Notonecta viridis Delcourt, 1909 (Africa, Europe, Asia)