Wikisource:Authors-O

Oa

 * Oakeley, Sir Herbert Stanley (1830–1903)
 * Oakley, Kenneth (1911–1981)

Ob

 * Obama, Barack (b. 1961)
 * Ober, Frederick A. (1849–1913)
 * Oberholtzer, Ellis Paxson (1868–1936)
 * Obrecht, Edmond M. (1852–1935)
 * Obretenova, Klara (–)
 * O'Brien, Edward Joseph Harrington (1890–1941)
 * O'Brien, John (1878–1952)
 * O'Brien, John J. (c. 1876–?)
 * O'Brien, Richard Barry (1847–1918)
 * Obrovský, Jakub (1882–1949)

Oc

 * O'Callaghan, Edmund Bailey (1797–1880)
 * Occleve, Thomas (or Hoccleve, 1368–1426)
 * Ockley, Simon (1678–1720)
 * O'Connell, Marjorie (b. 1890)
 * O'Connor, Sandra Day (b. 1930)

Od

 * Odesser, Yisroel Ber (1888–1994)
 * Odling, William (1829–1921)
 * Odlum, Victor (1880–1971)
 * O'Donnell, John Francis (1837–1874)
 * O'Donoghue, David James (1866–1917)
 * O'Donoghue, Freeman Marius (1849–1929)
 * Odoacer, Flavius (433–493)
 * Odvarka, Anton (1866–1929)

Oe/Œ/Ōe

 * Ōe no Chisato (9th–10th cent.)
 * Ōe no Masafusa (1041–1111)
 * Œnopides of Chios (c. 500 B.C.E.–fl/450 B.C.E.)
 * Oehlenschläger, Adam Gottlob (1779–1850)
 * Oelsner, Hermann (1871–1923)
 * Oestreich, Thomas (1872–1943)

Of

 * Offenbach, Jacques (1819–1880)
 * Offord, Robert Marshall (1846–1924)
 * O'Flanagan, James Roderick (1814–1900)

Og

 * Ogden, Charles Kay (1889–1957)
 * Ogilvie, William Heneage (1887–1971)
 * O'Gorman, Thomas (1843–1921)

Oh

 * O'Halloran, Joseph Sylvester (1842–1920)
 * O'Hara, Geoffrey (1882–1967)
 * Ohm, Georg Simon (1789–1854)

Ok

 * O'Kelley, Raymond F. (?–?)
 * Okey, Thomas (1852–1935)
 * Okudo, Jerome
 * Okune, Angela

Ol

 * Olcott, George N. (1869–1912)
 * Olcott, Henry Steel (1832–1907)
 * Old Man, The (1869–1936)
 * Olden, Thomas (1823–1900)
 * Oldenburg, Henry (1619–1677)
 * Oldfather, William Abbott (1880–1945)
 * Oldfield, Josiah (1863–1953)
 * Oldham, Charles (1868–1942)
 * Oldham, John (1653–1683)
 * Oldham, Richard Dixon (1858–1936)
 * O'Leary, John (1830–1907)
 * Oliger, Livarius (1875–1951)
 * Oliphant, Margaret Oliphant (1828–1897)
 * Oliver, Francis Wall (1864–1951)
 * Oliver, Samuel Pasfield (1838–1907)
 * Ollier, Charles (1788–1859)
 * Olrik, Axel (1864–1917)
 * Olsen, Alfred Johannes (1884–1956)
 * Olson, Julius Emil (1858–1944)

Om

 * O'Malley, Lewis Sydney Steward (1874–1941)
 * O'Meara, Eugene Henry (1815–1880)
 * * dell'Omo, Roberto
 * Omond, George William Thomson (1846–1929)
 * Omori, Annie Shepley (1856–1941/3)

On/Ōn

 * Ōnakatomi no Yoshinobu (921–991)
 * O'Neill, Elizabeth (1877–1951)
 * O'Neill, Eugene (1888–1953)
 * Ono no Komachi (c. 825–c. 900)
 * Ono no Takamura (802–852)
 * Onslow, 4th Earl of Onslow, William Hillier (1853–1911)

Op

 * Opitz, Martin (1597–1639)
 * Opolský, Jan (1875–1942)
 * Oppenheim, Edward Phillips (1866–1946)
 * Oppert, Ernst Jakob (1832–1903)
 * Oppert, Julius (1825–1905)
 * Oppius, Gaius (1st century BCE)

Or

 * Orczy, Emma (1865–1947)
 * Ordzhonikidze, Grigoriy (1886–1937)
 * O'Reilly, Bernard (1820–1907)
 * O'Reilly, John Boyle (1844–1890)
 * Orelli, Aloys von (1827–1892)
 * Oresme, Nicole (c. 1320-1325–1382)
 * Orme, Eliza (1848–1937)
 * Ormsby, John (1829–1895)
 * Orred, Meta (1846–1925)
 * Orton, Edward (1829–1899)
 * Orton, Lawrence D. (1941–)
 * Orwell, George (1903–1950)
 * Oxford, Edward de Vere, Earl of (1550–1604)

Os/Ōs

 * Osborn, Christabel (1868–1933)
 * Osborn, George (1808–1891)
 * Osborn, Henry Fairfield (1857–1935)
 * Osborn, Herbert (1856–1954)
 * Osborn, Sherard (1822–1875)
 * Osborne, Selleck (1783–1826)
 * Osbourne, Lloyd (1868–1947)
 * Osgood, Frances Sargent (1811–1850)
 * Osgood, Herbert Levi (1855–1918)
 * O'Shaughnessy, Arthur William Edgar (1844–1881)
 * Ōshikōchi no Mitsune (9th–10th cent.)
 * Osler, William (1849–1919)
 * Osmeña, Sergio (1878–1961)
 * Ossendowski, Ferdynand Antoni (1878–1945)
 * Ostrom, John Ward (1903–1993)
 * Ostwald, Wilhelm (1853–1934)
 * Ostrogorski, Moisey Yakovlevich (1854–1921)
 * O'Sullivan, Alexander Charles (1858–1924)
 * O'Sullivan, John L. (1813–1895)
 * Oswald, Felix Leopold (1845–1906)
 * Oswald, Lee Harvey (1939–1963)

Ot/Ōt

 * Ōtomo no Yakamochi (718–785)
 * O'Toole, George (b. 1947)
 * Otté, E. C. (1818–1903)
 * Otto the Great (912–973)
 * Otto III (980–1002)
 * Ottolengui, Rodrigues (1861–1937)
 * Otty, George (1820–1888)

Ou

 * Oudney, Walter (1790–1824)
 * Ould, Robert (1820–1882)
 * Ouseley, Sir Frederick Arthur Gore (1825–1889)
 * Oustalet, Émile (1844–1905)
 * Outler, Albert Cook (1908–1989)
 * Oughtred, William (1575–1660)

Ov

 * Overbeck, Johann Friedrich (1789–1869)
 * Miss Overton (fl. 1860s)
 * Overton, John Henry (1835–1903)
 * Ovid (43 BCE–17 CE)

Ow

 * Owen, Douglas (1850–1920)
 * Owen, Edmund (1847–1915)
 * Owen, John (1616–1683)
 * Owen, Richard (1804–1892)
 * Owen, Robert Latham (1856–1947)
 * Owen, Sidney George (1858–1940)
 * Owen, Wilfred (1893–1918)
 * Owen, William (1750–1830)
 * Owgan, Henry (1819–1885)