O

• Alejandro Obregón (1920–1992), Colombian painter, muralist, sculptor and engraver
• Bencho Obreshkov (1899–1970), Bulgarian painter
• Jacques-François Ochard (1800–1870), French artist and teacher
• Jacob Ochtervelt (1634–1682)
• Leonard Ochtman (1854–1935), American Impressionist painter
• Ogata Gekkō (1859–1920)
• Ogata Kenzan (1663–1743)
• Ogata Kōrin (1658–1716)
• Juan O'Gorman (1905–1982), Mexican painter and architect
• Ogura Yuki (1895–2000)
• Dorothea Warren O'Hara (1873–1972), American ceramic artist
• Ohara Koson (1877–1945)
• Doug Ohlson (1936–2010)
• Michalis Oikonomou (1888–1933)
• Okada Beisanjin (1744–1820)
• Okada Hanko (1782–1846)
• Okamoto Tarō (1911–1996)
• Georgia O'Keeffe (1887–1986), American artist
• Aloysius O'Kelly (1853–1941)
• Okuda Gensō (1912–2003)
• Okumura Masanobu (1686–1764)
• Okumura Togyu (1889–1990)
• Jules Olitski (1922–2007), American abstract painter, printmaker, and sculptor
• Viktor Oliva (1861–1928), Czech painter and illustrator
• Nathan Oliveira (1928–2010), American painter, printmaker, and sculptor
• Olivia Peguero (born 1963), Dominican American painter and sculptor
• Ceferí Olivé (1907–1995), Catalan watercolor painter
• Madge Oliver (1875–1924), British painter
• Francisco Oller (1833–1917)
• Frank O'Meara (1853–1888)
• Onchi Koshiro (1891–1955)
• Julian Onderdonk (1882–1922)
• Ono Tadashige (1909–1990)
• Maria van Oosterwijk (1630–1693), Dutch Baroque painter, specializing in still-lifes
• Bruce Onobrakpeya (born 1932), printmaker, painter and sculptor
• John Opie (1761–1807), Cornish historical and portrait painter
• Andrea Orcagna (1320–1368), Italian painter, sculptor, and architect
• William Quiller Orchardson (1835–1910), Scottish portraitist and painter of domestic and historical subjects
• Edward Otho Cresap Ord, II (1858–1923), American painter & poet
• Bryan Organ (born 1935), English painter
• Emil Orlik (1870–1932), Austrian painter, etcher, and lithographer
• Aleksander Orłowski (1777–1832), Polish painter, sketch maker, and pioneer of lithography
• José Clemente Orozco (1883–1949), Mexican social realist painter
• Sir William Orpen (1878–1931), Irish portrait painter
• Manuel Ortiz de Zarate (1887–1946), Chilean painter
• George Earl Ortman (1926–2015)
• Erik Ortvad (1917–2008), Danish painter, founding member of the COBRA avant-garde movement
• Walter Osborne (1859–1903)
• Adriaen van Ostade (1610–1685), Dutch genre painter
• Isaac van Ostade (1621–1649)
• Ilya Ostroukhov (1858–1929)
• Ota Masamitsu (1892–1975)
• Otake Chikuha (1878-1936)
• Johann Friedrich Overbeck (1789–1869), German painter and member of the Nazarene movement
• Auseklis Ozols (born 1941), American painter and teacher