List of people by name: A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z
Oa-Ok - Ol-Oo - Op-Oz
- Oparin, Aleksandr, (died 1980)
- Opazo, Pedro, president
- Opel, Adam, (born 1837), German engineer and industrialist
- Opeth, musician
- Ophüls, Max, (1902-1957), film director
- Opie, John, (1761-1807), painter
- Oppen, George, poet
- Oppenheimer, Harry, (1908-2000), businessman
- Oppenheimer, J. Robert, (1904-1967), US physicist
- Orage, Alfred, (1873-1934), journalist
- Oramus, Marek, author
- Orantes, Manuel, (Spain)
- Orbach, Jerry, (born 1935), Canadian actor
- Orbison, Roy, (1936-1988), US singer
- Orcagna, Andrea, (1320-1368), artist
- Orchard, Energy, musician
- Orchardson, Sir William Quiller, (1835-1910), painter
- Ordono I of Asturias, (830?-866), Asturian monarch
- O'Ree, Willie, hockey player
- O'Reilly, Emily, journalist
- Orelli, Johann Caspar von (1787-1849)
- Oresme, Nicole, scholastic philosopher
- Orff, Carl, (1895-1982), German composer
- Organ, Bryan, (born 1935), painter
- Origen, (182-251)
- Orion, Jack, musician
- Orkeny, Istvan, (1912-1979), novelist
- Orlando, Tony, (born 1944), musician
- Orlando, Vittorio
- Orlik, Emil, (1870-1932), painter and graphic artist
- Orlovsky, Peter, (beat)
- Orlowski, Aleksander, Polish painter
- Orman, Kate, science fiction author
- Ormandy, Eugene, (1899-1985), conductor
- Ornstein, Leo, (1892-2002)
- Orono, Rafael, world champion boxer
- O'Rourke, Colm, footballer
- O'Rourke, Heather, (1975-1988), actress
- O'Rourke, Mary, politician
- O'Rourke, P. J, (born 1947)
- Orozco, José Clemente, (1883-1949), Mexican artist
- Orpen, Sir William, (1878-1931), painter
- Orr, Bobby, (b 1948) Canadian Hockey player
- Orser, Brian, (born 1961), figure skater
- Ørsted, Hans Christian, (1777-1851), Danish physicist
- Orta, Garcia da, botanist
- Ortega, Daniel, (born 1945), president of Nicaragua
- Ortelius, Abraham, (1527-1598), Belgian cartographer
- Ortiz, Carlos, (born 1939), world champion boxer
- Ortiz, Jose basketball player
- Ortiz, Luis (born c. 1962) Puerto Rican boxer
- Ortiz, Luis "Perico Puerto Rican musician
- Ortiz, Manuel, boxer
- Ortiz, Shalym, actor and singer
- Ortiz, Tito, (born 1975), Ultimate Fighting champion
- Ortleb, Rainer, FDP
- Ortoli, Francois-Xavier, European Commission President
- Orton, Beth, musician
- Orton, Joe, (1933-1967), dramatist
- Ortu, Francesco Cocco
- Ortvad, Erik, (born 1917), painter
- Orwell, George, (1903-1950), British author
- Orzabal, Roland, (born 1961), singer, guitarist
- Orzeszkowa, Eliza, (1841-1910), novelist
- Osborne, Adam, (died 2003), computer pioneer
- Osborne, Jeffrey, (born 1948), singer
- Osborne, Joan, (born 1963), musician
- Osborne, John, (1929-1994), dramatist
- Osborne, Milton, Australian historian
- Osbourne, Kelly, (born 1984), US singer
- Osbourne, Mary Pope, author
- Osbourne, Ozzy, (born 1948), US heavy rock singer
- Osbourne, Sharon, (born 1952), wife of Ozzy Osbourne
- Oscar I of Sweden, (1799-1859)
- Oscar II of Sweden, (1829-1907)
- Osceola, (1804-1838)
- Osendarp, Tinus, (1916-2002), athlete
- Osgood, Charles, (born 1933), journalist, commentator
- Osgood, Chris, hockey player
- Osgood, Peter, (born 1947), English football player
- O' Shane, Tjandamurra (born 1962) aborigene who was a crime victim
- O'Shea, Kitty, mistress
- Oshima, Nagisa, Japanese film director
- Oslak, Vinko, (born 1947), poet
- Osler, William, (1849-1919)
- Osman II, (died 1622), Turkish sultan
- Osmena, Sergio, president of Philippines
- Osment, Haley Joel, (born 1988), actor
- Osmond, Donny, (born 1957), entertainer
- Osmond, Marie, (born 1959), singer, actress, television host
- Osojnik, Iztok, (born 1951), poet
- Ospitone
- Ossietzky, Carl von, (1889-1938), journalist and pacifist
- Ossman, Vess, (1868-1923), musician
- Ostade, Adriaen van, (1610-1685), painter
- Ostanek, Walter, musician
- Ostashek, John
- Ostermaier, Albert, dramatist, author
- Osti, Josip, (born 1945), poet
- Ostir, Karel, (1888-1973), linguist
- Ostrogradsky, Mikhail Vasilievich, (1801-1862), mathematician
- Ostwald, Wilhelm, (1853-1932), chemist
- O'Sullivan, Gilbert, (born 1946), singer
- O'Sullivan, Maureen, (1911-1998), actress, mother of Mia Farrow
- O'Sullivan, Sonia, Olympic medal winner
- Oswald of Bernicia, (633-641), British monarch
- Oswald, Lee Harvey, (1939-1963), assumed US murderer of J.F. Kennedy
- Oswald, Stephen, astronaut
- Oswiu of Northumbria, (641-670), Anglo-Saxon king
- Oteri, Cheri, US comedienne
- Otho, Roman emperor
- Otis, James, (1725-1783), American revolutionary advocate
- Otis, Mercy: see Mercy Otis Warren
- Otis, Samuel, (1740-1814), secretary to US Senate
- Otis, Johnny, musician
- O'Toole, Peter, (born 1932), actor
- Ott, Mel, (born 1909), baseball player
- Otter, Ann-Sofie von, (born 1955), Swedish musician
- Otto the Great, (912-973), king, emperor
- Otto II, Holy Roman Emperor, (955-983), emperor
- Otto III, Holy Roman Emperor, (980-1002), king, emperor
- Otto IV, Holy Roman Emperor, (1208-1215), king, emperor
- Otto of Bavaria, (1848-1916), King of Bavaria
- Otto of Greece, (1832-1862), Bavarian prince offered the throne
- Otto, Nikolaus, (1832-1891), engineer
- Otto, Rudolf, philosopher
- Otway, Thomas, English playwright
- Oud, J.J.P, architect
- Oudinot, Nicolas, (1767-1847), French marshal
- Ouida, (1839-1908), English novelist
- Ousmane, Sembene, Senegalese writer
- Ouspenskaya, Maria, (1876-1949), actor
- Outhwaite, Ida Rentoul, (born 1888), Australian illustrator
- Outinen, Kati, Finnish actress
- Outram, James, (1864-1925), early explorer of the Canadian Rockies
- Ovalle, José Tomás, president
- Overath, Wolfgang, athlete
- Overbeck, Johann Friedrich, (1789-1869), painter
- Overmyer, Robert, astronaut
- Overton, John H, (1875-1948), USA congressman
- Ovid, (43 BC-17 AD), Roman poet
- Ovitz, Michael, (born 1946), film producer
- Owen, Bill, (1914-1999), songwriter
- Owen, Daniel, (1836-1895), novelist
- Owen, Michael, (born 1979), soccer player
- Owen, Richard, (1804-1892), biologist
- Owen, Wilfred, (1893-1918), English poet
- Owens, Buck, (born 1929), singer-songwriter, musician
- Owens, Jesse, (1913-1980), US black track & field athlete
- Owens, Steve, (born 1947), football player
- Oxenstierna, Axel, (1583-1654), Swedish politician
- Oxenstierna, Bengt, (1623-1702), Swedish politician
- Oxenstierna, Gabriel, (1587-1640), Swedish politician
- Oxenstierna, Johan, (1611-1657), Swedish politician
- Oyanedel, Abraham, president
- Oz, Amos, (born 1937), author
- Oz, Frank, (born 1944), US puppeteer, director
- Ozal, Turgut, president
- Ozanne, Edward Chepmell, (1915-1922), British bailiff
- Ozawa, Jisaburo, Japanese admiral
- Ozawa, Seiji, (born 1935), Japanese conductor
- Ozols, Auseklis, (born 1941), painter
- Ozu, Yasujiro, (1903-1963), Japanese film director