• Ostrea Linnaeus, 1758
• Ostrea (Alectryonella) Sacco, 1897 accepted as Alectryonella Sacco, 1897
• Ostrea (Alectryonia) Fischer von Waldheim, 1807 accepted as Lopha Röding, 1798
• Ostrea (Alectryonia) alicula Hamlin, 1884 † (uncertain > unassessed)
• Ostrea (Alectryonia) baribisiana K. Martin, 1909 † accepted as Lopha baribisiana (K. Martin, 1909) †
• Ostrea (Alectryonia) caboblanquensis Weisbord, 1964 †
• Ostrea (Alectryonia) chlamydoides K. Martin, 1922 † accepted as Lopha chlamydoides (K. Martin, 1922) †
• Ostrea (Alectryonia) junghuhni K. Martin, 1909 † accepted as Lopha junghuhni (K. Martin, 1909) †
• Ostrea (Alectryonia) longifolium K. Martin, 1922 † accepted as Lopha longifolia (K. Martin, 1922) †
• Ostrea (Alectryonia) simoensis K. Martin, 1909 † accepted as Lopha simoensis (K. Martin, 1909) †
• Ostrea (Alectryonia) strambergensis G. Boehm, 1883 † (uncertain > unassessed)
• Ostrea (Alectryonia) tithonia G. Boehm, 1883 † (uncertain > unassessed)
• Ostrea (Anodontostrea) Suter, 1917 accepted as Ostrea Linnaeus, 1758
• Ostrea (Bellostrea) Vialov, 1936 † represented as Ostrea Linnaeus, 1758
• Ostrea (Bellostrea) bellovacina Lamarck, 1806 † accepted as Ostrea bellovacina Lamarck, 1806 †
• Ostrea (Crassostrea) Sacco, 1897 accepted as Crassostrea Sacco, 1897
• Ostrea (Crassostrea) yoshimoensis T. Kobayashi & K. Suzuki, 1939 † (uncertain > unassessed)
• Ostrea (Cubitostrea) Sacco, 1897 † accepted as Cubitostrea Sacco, 1897 †
• Ostrea (Cymbulostrea) Sacco, 1897 † accepted as Crassostrea Sacco, 1897
• Ostrea (Dendostrea) Swainson, 1835 accepted as Dendostrea Swainson, 1835
• Ostrea (Exogyra) Say, 1820 † accepted as Exogyra Say, 1820 †
• Ostrea (Exogyra) jonesiana Tate, 1867 † (uncertain > unassessed)
• Ostrea (Exogyra) lingulata Lycett, 1863 † (uncertain > unassessed)
• Ostrea (Exogyra) subreniformis Étallon, 1862 † (uncertain > unassessed)
• Ostrea (Gigantostrea) Sacco, 1897 † accepted as Pycnodonte Fischer von Waldheim, 1835
• Ostrea (Gigantostrea) gittosina A. W. B. Powell & Bartrum, 1929 † accepted as Crenostrea gittosina (A. W. B. Powell & Bartrum, 1929) †
• Ostrea (Gryphaea) Lamarck, 1801 † accepted as Gryphaea Lamarck, 1801 †
• Ostrea (Gryphaea) pinguis Étallon, 1862 † (uncertain > unassessed)
• Ostrea (Liostrea) Douvillé, 1904 † accepted as Liostrea Douvillé, 1904 †
• Ostrea (Liostrea) cimana L. R. Cox, 1949 † (uncertain > unassessed)
• Ostrea (Ostrea) Linnaeus, 1758 represented as Ostrea Linnaeus, 1758
• Ostrea (Ostrea) caraboboensis Weisbord, 1964 † represented as Ostrea caraboboensis Weisbord, 1964 †
• Ostrea (Ostrea) contejeani Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) ermontiana Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) langii Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) lixula Weisbord, 1964 † accepted as Ostrea stentina Payraudeau, 1826
• Ostrea (Ostrea) nanjiangensis J.-M. Wei, 1984 † (uncertain > unassessed)
• Ostrea (Ostrea) njalindungensis K. Martin, 1921 † represented as Ostrea njalindungensis K. Martin, 1921 †
• Ostrea (Ostrea) pannucea Weisbord, 1964 † represented as Ostrea pannucea Weisbord, 1964 †
• Ostrea (Ostrea) quadrata Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) semisolitaria Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) sequana Thurmann, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) subnana Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) subsolitaria Étallon, 1862 † (uncertain > unassessed)
• Ostrea (Ostrea) thurmanni Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Ostrea) vallata Étallon, 1863 † (uncertain > unassessed)
• Ostrea (Saccostrea) Dollfus & Dautzenberg, 1920 accepted as Saccostrea Dollfus & Dautzenberg, 1920
• Ostrea (Turkostrea) Vialov, 1936 † represented as Ostrea Linnaeus, 1758
• Ostrea (Turkostrea) multicostata Deshayes, 1832 † accepted as Ostrea multicostata Deshayes, 1832 †
• Ostrea abrupta A. d'Orbigny, 1843 † (uncertain > unassessed)
• Ostrea aculeata Gmelin, 1791 accepted as Mimachlamys varia (Linnaeus, 1758)
• Ostrea acuminata J. Sowerby, 1816 † accepted as Praeexogyra acuminata (J. Sowerby, 1816) †
• Ostrea adansoni Rochebrune, 1905 accepted as Crassostrea tulipa (Lamarck, 1819)
• Ostrea adriatica Lamarck, 1819 accepted as Ostrea edulis Linnaeus, 1758
• Ostrea aequatorialis A. d'Orbigny, 1846 accepted as Crassostrea aequatorialis (A. d'Orbigny, 1846)
• Ostrea alabamiensis I. Lea, 1833 † accepted as Striostrea alabamiensis (I. Lea, 1833) † accepted as Striostrea gigantissima (J. Finch, 1824) †
• Ostrea alatus Gmelin, 1791 accepted as Isognomon alatus (Gmelin, 1791)
• Ostrea albatra Jousseaume, 1925 accepted as Dendostrea sandvichensis (G. B. Sowerby II, 1871)
• Ostrea albicans Schröter, 1802 accepted as Pecten albicans (Schröter, 1802)
• Ostrea algoensis G. B. Sowerby II, 1871
• Ostrea alvarezii A. d'Orbigny, 1839 † accepted as Cubitostrea alvarezii (A. d'Orbigny, 1839)
• Ostrea alveatula Jousseaume, 1925 accepted as Neopycnodonte cochlear (Poli, 1795)
• Ostrea amara P. P. Carpenter, 1864 accepted as Saccostrea palmula (P. P. Carpenter, 1857)
• Ostrea amasa (Iredale, 1939) accepted as Saccostrea scyphophilla (F. Péron & Lesueur, 1807)
• Ostrea ameghinoi Ihering, 1902 † (uncertain > unassessed)
• Ostrea amorpha G. B. Sowerby I, 1846 † (uncertain > taxon inquirendum)
• Ostrea anatina Gmelin, 1791 accepted as Malleus anatinus (Gmelin, 1791)
• Ostrea angasi G. B. Sowerby II, 1871
• Ostrea angasi var. digitata E. Lamy, 1929 accepted as Ostrea chilensis Küster, 1844
• Ostrea angelica Rochebrune, 1895
• Ostrea angulata (Lamarck, 1819) accepted as Crassostrea angulata (Lamarck, 1819) accepted as Magallana angulata (Lamarck, 1819)
• Ostrea angustata de Serres, 1843 † accepted as Crassostrea gryphoides (Schlotheim, 1813) †
• Ostrea anomialis Lamarck, 1819 † accepted as Anomia anomialis (Lamarck, 1819) †
• Ostrea anonyma Gmelin, 1791 accepted as Laevichlamys squamosa (Gmelin, 1791)
• Ostrea antarctica Zinsmeister, 1984 † accepted as Pycnodonte antarctica (Zinsmeister, 1984) †
• Ostrea antecursor Weisbord, 1964 †
• Ostrea arata Gmelin, 1791 accepted as Karnekampia sulcata (O. F. Müller, 1776)
• Ostrea arborea Dillwyn, 1817 (uncertain > nomen dubium)
• Ostrea arborea Dillwyn, 1817 sensu Dunker, 1882 accepted as Crassostrea ariakensis (Fujita, 1929) accepted as Magallana ariakensis (Fujita, 1929)
• Ostrea arcuata Brocchi, 1814 † accepted as Gigantopecten arcuatus (Brocchi, 1814) †
• Ostrea arcula Marwick, 1928 †
• Ostrea arenicola Tate, 1886 †
• Ostrea ariakensis Fujita, 1929 accepted as Magallana ariakensis (Fujita, 1929)
• Ostrea armata Goldfuss, 1833 † (uncertain > unassessed)
• Ostrea arrosis Aldrich, 1904 † (uncertain > taxon inquirendum)
• Ostrea atherstonei R. B. Newton, 1913
• Ostrea aupouria Dinamani, 1981 accepted as Ostrea equestris Say, 1834
• Ostrea aurantia Gmelin, 1791 accepted as Flexopecten glaber (Linnaeus, 1758)
• Ostrea auricularis Münster, 1833 † (uncertain > unassessed)
• Ostrea australis Lamarck, 1819 accepted as Pustulostrea australis (Lamarck, 1819)
• Ostrea avalitesensis Jousseaume, 1925 (uncertain > taxon inquirendum)
• Ostrea awajiensis Matsubara, 1998 †
• Ostrea bataviana K. Martin, 1885 †
• Ostrea bellovacina Lamarck, 1806 †
• Ostrea beneckei Möricke, 1896 † accepted as Crassostrea transitoria (Hupé, 1854) †
• Ostrea benefica Bartsch, 1945 accepted as Crassostrea belcheri (G. B. Sowerby II, 1871) accepted as Magallana belcheri (G. B. Sowerby II, 1871)
• Ostrea biauriculata Lamarck, 1806 † accepted as Pycnodonte biauriculata (Lamarck, 1806) †
• Ostrea bicolor Hanley, 1846 accepted as Crassostrea tulipa (Lamarck, 1819)
• Ostrea bilineata Röding, 1798 accepted as Magallana bilineata (Röding, 1798)
• Ostrea blandina A. d'Orbigny, 1850 † accepted as Atreta blandina (A. d'Orbigny, 1850) †