Oblongocoris Bai, Heiss & Cai, 2020, Genus
Ochetopus Hahn, 1833, Genus – synonym of Pygolampis Germar, 1817, Genus
Ochetostethus Fieber, 1860, Genus
Ochrodema Reuter, 1899, Genus – synonym of Maurodactylus Reuter, 1878, Genus
Ochteridae Kirkaldy, 1906, Familia
Ochterus Latreille, 1807, Genus
Ochtherus Agassiz, 1847, Genus – misspelled name of Ochterus Latreille, 1807, Genus
Ochyrotylus Jakovlev, 1885, Genus
Octacysta Drake & Ruhoff, 1960, Genus – synonym of Dictyla Stål, 1874, Genus
Ocypus Montrouzier, 1861, Genus – homonym of Coridromius Signoret, 1862, Genus
Odhiamboella Schuh, 1974, Genus – synonym of Psallomimus Wagner, 1951, Genus
Odius Stål, 1868, Genus – synonym of Caystrus Stål, 1861, Genus
Odonia Bergroth, 1889, Genus – synonym of Eumenotes Westwood, 1846, Genus
Odonscelis Mulsant & Rey, 1865, Genus – misspelled name of Odontoscelis Laporte, 1833, Genus
Odontarsus Mulsant & Rey, 1865, Genus – misspelled name of Odontotarsus Laporte, 1833, Genus
Odontonotus Kormilev, 1955, Genus
Odontoplatys Fieber, 1858, Genus
Odontopus Laporte, 1833, Genus – homonym of Probergrothius Kirkaldy, 1904, Genus
Odontoscelinae Amyot & Serville, 1843, Subfamilia
Odontoscelis Laporte, 1833, Genus
Odontotarsiellus Hoberlandt, 1955, Genus
Odontotarsinae Mulsant & Rey, 1865, Subfamilia
Odontotarsus Laporte, 1833, Genus
Oedocoris L.Y. Zheng & G.Q. Liu, 1987, Genus – synonym of Lakhonia Yang, 1936, Genus
Oenusa Stål, 1874, Genus – synonym of Lisarda Stål, 1859, Genus
Oestopis Distant, 1879, Genus – synonym of Bolaca Walker, 1867, Genus
Oimoctes Gistel, 1848, Genus – synonym of Gastrodes Westwood, 1840, Genus
Oligocoris Jordan, 1944, Genus – synonym of Fulvius Stål, 1862, Genus
Oligotylus Van Duzee, 1916b, Genus – synonym of Psallus Fieber, 1858, Genus
Olympiocapsus Kirkaldy, 1902d, Genus – synonym of Eurystylus Stål, 1871, Genus
Omaniidae Cobben, 1970, Familia
Omanocoris Kiritshenko, 1916, Genus
Ommatoplinthisus Carapezza, 1984, Genus – synonym of Camptocera Jakovlev, 1877, Genus
Omocoris Lindberg, 1930, Genus
Omphalonotus Reuter, 1876, Genus
Oncauchenius Stål, 1872, Genus – synonym of Rhynocoris Hahn, 1833, Genus
Oncinoproctus Breddin, 1904, Genus
Oncocephalinae Villiers, 1960, Subfamilia – synonym of Stenopodainae Amyot & Serville, 1843, Subfamilia
Oncocephalus Klug, 1830, Genus
Oncognathus Fieber, 1858, Genus – homonym of Stenotus Jakovlev, 1877, Genus
Oncoma Fieber, 1860, Genus – synonym of Brachynema Mulsant & Rey, 1852, Genus
Oncomerinae Stål, 1870, Subfamilia
Oncotylidea Wagner, 1965, Genus
Onychomesa Wygodzinsky, 1966, Genus
Onychotrechus Kirkaldy, 1903, Genus
Onychumenus Reuter, 1879e, Genus – synonym of Lopus Hahn, 1831, Genus
Onylia Mulsant & Rey, 1866, Genus – synonym of Stagonomus Gorski, 1852, Genus
Ophthalmiciens Fairmaire, 1884, Subfamilia – synonym of Geocorinae Dahlbom, 1851, Subfamilia
Ophthalmicus Schilling, 1829, Genus – synonym of Geocoris Fallén, 1814, Genus
Ophthalmicus: Stål, 1862, Genus – invalid name of Acompus Fieber, 1860, Genus
Ophthalmicus: Stål, 1862, Genus – invalid name of Aphanus Laporte, 1833, Genus
Ophthalmicus: Stål, 1862b, Genus – misidentification of Stygnocoris Douglas & Scott, 1865, Genus
Ophthalmocoris Zetterstedt, 1838, Genus – synonym of Labops Burmeister, 1835, Genus
Opinus Laporte, 1833, Genus – synonym of Tapeinus Laporte, 1833, Genus
Opinus: Stål, 1859, Genus – misidentification of Staliastes Kirkaldy, 1900, Genus
Opistholeptus Bergroth, 1894, Genus
Opisthostenus Reuter, 1882, Genus – homonym of Opistholeptus Bergroth, 1894, Genus
Opisthotaenia Reuter, 1901, Genus
Opistoplatys Westwood, 1835, Genus
Oplistochilus Jakovlev, 1887, Genus
Oplistopus Jakovlev, 1874, Genus – synonym of Reduvius Fabricius, 1775, Genus
Opsicoetus Klug, 1830, Genus – synonym of Reduvius Fabricius, 1775, Genus
Oraniella Reuter, 1894, Genus – synonym of Orthocephalus Fieber, 1858, Genus
Oreada Mulsant & Mayet, 1868, Genus – synonym of Holotrichius Burmeister, 1835, Genus
Oreinocorixa White, 1873, Genus – synonym of Glaenocorisa Thomson, 1869, Genus
Oreocapsus Linnavuori, 1975, Genus
Oreolygus Linnavuori, 1974, Genus – invalid name of Oreolygus Linnavuori, 1975, Genus
Oreolygus Linnavuori, 1975, Genus
Orientocapsus Yasunaga & Schwartz, 2007, Genus
Orientocydnus J.A. Lis, 1994, Genus – synonym of Cydnus Fabricius, 1803, Genus
Orientomiris Yasunaga, 1997, Genus
Orieotrechus Scudder, 1962, Genus
Origanaus Distant, 1893, Genus
Oronomiris Kirkaldy, 1902a, Genus – synonym of Trigonotylus Fieber, 1858, Genus
Orsillinae Stål, 1872, Subfamilia
Orsolia Wagner, 1965, Genus – synonym of Compsonannus Reuter, 1902, Genus
Orthocephalus Fieber, 1858, Genus
Orthonotus Stephens, 1829, Genus
Orthophrys Horváth, 1911, Genus
Orthophylus Duwal & Lee, 2011, Genus
Orthopidea Reuter, 1899, Genus
Orthosteira Fieber, 1844, Genus – synonym of Acalypta Westwood, 1840, Genus
Orthostira Fieber, 1861, Genus – misspelled name of Acalypta Westwood, 1840, Genus
Orthotylellus Knight, 1935, Genus – synonym of Sthenaridea Reuter, 1885, Genus
Orthotylinae Van Duzee, 1916, Subfamilia
Orthotylus Fieber, 1858, Genus
Osmania Kiyak, 1999, Genus – synonym of Byrsinus Fieber, 1860, Genus
Ossipaga Distant, 1918a, Genus – synonym of Ninus Stål, 1860, Genus
Ossipaga Distant, 1918a, Genus – synonym of Ninus Stål, 1860, Genus
Ostorodias Distant, 1904, Genus – synonym of Scoloposcelis Fieber, 1864, Genus
Ostorodiasoides Distant, 1913, Genus – synonym of Physopleurella Reuter, 1884, Genus
Otantestia Breddin, 1900, Genus
Oxycareninae Stål, 1862, Subfamilia
Oxycarenus Fieber, 1837, Genus
Oxydalus Mulsant & Rey, 1866, Genus – synonym of Elasmostethus Fieber, 1860, Genus
Oxydalus Mulsant & Rey, 1866b, Genus – synonym of Elasmostethus Fieber, 1860, Genus
Oxyprymna Stål, 1873, Genus – synonym of Elvisura Spinola, 1837, Genus