| ARTIST | BORN-DIED | PERIOD | SCHOOL |
O | O'CONNOR, James Arthur | (1792-1841) | Romanticism | Irish painter |
| OBBERGEN, Anthonis van | (1543-1611) | Northern Renaissance | Flemish architect (Poland) |
| OBICI, Giuseppe | (1807-1878) | Romanticism | Italian sculptor (Rome) |
| OBRIST, Hermann | (1862-1927) | Art Nouveau | Swiss sculptor (Munich) |
| OCAMPO, Andrés de | (c. 1550-1623) | Mannerism | Spanish sculptor (Seville) |
| OCHTERVELT, Jacob | (1634-1682) | Baroque | Dutch painter (Amsterdam) |
| ODEKERKEN, Willem van | (c. 1610-1677) | Baroque | Dutch painter (Delft) |
| ODERISI, Pietro | (active c. 1260-80) | Medieval | Italian sculptor |
| ODERISI, Roberto d' | (active c. 1330-1382) | Medieval | Italian painter (Naples) |
| ODERISIUS OF BENEVENTO | (active 1119-1150) | Medieval | Italian sculptor |
| ODEVAERE, Joseph-Denis | (1775-1830) | Neoclassicism | Flemish painter |
| OEHME, Ernst Ferdinand | (1797-1855) | Romanticism | German painter (Dresden) |
| OEVER, Hendrick ten | (1639-1716) | Baroque | Dutch painter (Zwolle) |
| OGGIONO, Marco d’ | (c. 1467-1524) | Mannerism | Italian painter |
| OGNABENE, Andra di Jacopo (see ANDREA DI JACOPO D'OGNABENE) | (active 1286-1317) | Medieval | Italian goldsmith |
| OHLMÜLLER, Joseph Daniel | (1791-1839) | Neoclassicism | German architect (Munich) |
| OLBRICH, Josef Maria | (1867-1908) | Art Nouveau | Austrian architect (Darmstadt) |
| OLIS, Jan | (c. 1610-1676) | Baroque | Dutch painter |
| OLIVEIRA, Mateus Vicente de | (1706-1785) | Baroque | Portuguese architect (Lisbon) |
| OLIVER, Isaac | (before 1568-1617) | Baroque | English miniaturist |
| OLIVER, Peter | (c. 1594-1647) | Baroque | English painter |
| OLIVIER, Ferdinand | (1785-1841) | Romanticism | German painter |
| OLIVIERI, Giovanni Domenico | (1708-1762) | Baroque | Italian sculptor (Madrid) |
| OLIVIERI, Pier Paolo | (1551-1599) | Mannerism | Italian sculptor (Rome) |
| OLLIVIER, Michel-Barthélémy | (1712-1784) | Neoclassicism | French painter (Paris) |
| OMMEGANCK, Balthazar Paul | (1755-1826) | Rococo | Flemish painter (Antwerp) |
| OMODEO, Giovanni Antonio (see AMADEO, Giovanni Antonio) | (c. 1447-1522) | Early Renaissance | Italian architect (Lombardy) |
| ONGARO (see FABRIS, Michele) | (c 1644-1684) | Baroque | Hungarian sculptor (Venice) |
| OOST, Jacob van, the Elder | (1603-1671) | Baroque | Flemish painter (Bruges) |
| OOST, Jacob van, the Younger | (1639-1713) | Baroque | Flemish painter (Bruges) |
| OOSTEN, Izaac van | (1613-1661) | Baroque | Flemish painter (Antwerp) |
| OOSTERWIJK, Maria van | (1630-1693) | Baroque | Dutch painter |
| OOSTSANEN, Jacob Cornelisz van (see CORNELISZ VAN OOSTSANEN, Jacob) | (c. 1472-1533) | Northern Renaissance | Netherlandish painter (Amsterdam) |
| OPIE, John | (1761-1807) | Rococo | English painter (London) |
| OPITZ, Georg Emanuel | (1775-1841) | Romanticism | German painter (Leipzig) |
| OPPENORDT, Alexandre-Jean | (1639-1715) | Baroque | French cabinet-maker (Paris) |
| OPPENORDT, Gilles-Marie | (1672-1742) | Baroque | French architect (Paris) |
| OPSTAL, Gerard van | (1594-1668) | Baroque | Flemish sculptor (Paris) |
| ORBETTO (see TURCHI, Alessandro) | (1578-1649) | Baroque | Italian painter (Verona) |
| ORCAGNA | (c. 1308-c. 1368) | Medieval | Italian sculptor (Florence) |
| ORDÓÑEZ, Bartolomé | (c. 1490-1520) | High Renaissance | Spanish sculptor |
| OREMBELLI MASTER (see TURA, Giovanni Francesco) | (c. 1485-c. 1546) | High Renaissance | Italian painter (Mantua) |
| ORIOLI, Pietro di Francesco degli | (1458-1496) | Early Renaissance | Italian painter (Siena) |
| ORIZZONTE (see BLOEMEN, Jan Frans van) | (1662-1749) | Baroque | Flemish painter (Rome) |
| ORLEY, Bernaert van | (1491/92-1542) | Northern Renaissance | Flemish painter (Brussels) |
| ORLEY, Jan van | (1665-1735) | Rococo | Flemish painter (Brussels) |
| ORLOVSKY, Aleksandr Osipovich | (1777-1832, ) | Romanticism | Russian painter (St. Petersburg) |
| ORLOVSKY, Boris Ivanovich | (1792-1837) | Neoclassicism | Russian sculptor |
| ORRENTE, Pedro | (1580-1645) | Baroque | Spanish painter (Valencia) |
| ORSI, Lelio | (1511-1587) | Mannerism | Italian painter |