| ARTIST | BORN-DIED | PERIOD | SCHOOL |
O | ORSI, Tranquillo | (1771-1845) | Neoclassicism | Italian painter (Venice) |
| ORSOLINO, Tommaso | (1587-1675) | Baroque | Italian sculptor (Genoa) |
| ORTELIUS, Abraham | (1528-1598) | Northern Renaissance | Flemish graphic artist (Antwerp) |
| ORTENSI, Francesco di Girolamo (see FRANCESCO DAL PRATO) | (1512-1562) | High Renaissance | Italian goldsmith (Florence) |
| ORTOLANO | (c. 1487-after 1524) | High Renaissance | Italian painter (Ferrara) |
| OS, Georgius van | (1782-1861) | Romanticism | Dutch painter (Paris) |
| OS, Jan van | (1744-1808) | Rococo | Dutch painter (The Hague) |
| OS, Pieter Gerardus van | (1776-1839) | Realism | Dutch painter (The Hague) |
| OSONA, Francisco de | (c. 1465-c. 1514) | Early Renaissance | Spanish painter (Valencia) |
| OSONA, Rodrigo de, the Younger | (active 1505-1530) | High Renaissance | Spanish painter (Valencia) |
| OSTADE, Adriaen Jansz. van | (1610-1685) | Baroque | Dutch painter (Haarlem) |
| OSTADE, Isaack van | (1621-1649) | Baroque | Dutch painter (Haarlem) |
| OSTENDORFER, Michael | (c. 1494-1549) | Northern Renaissance | German graphic artist (Regensburg) |
| OTTIN, Auguste | (1811-1890) | Realism | French sculptor (Paris) |
| OTTONI, Lorenzo | (1658-1736) | Baroque | Italian sculptor |
| OUDINÉ, Eugène André | (1810-1887) | Realism | French sculptor (Paris) |
| OUDRY, Jacques-Charles | (c. 1722-1778) | Rococo | French painter |
| OUDRY, Jean-Baptiste | (1686-1755) | Baroque | French painter |
| OUTIN, Pierre | (1840-1899) | Romanticism | French painter |
| OUVRIER, Jean | (1725-1784) | Rococo | French graphic artist (Paris) |
| OUWATER, Albert van | (active 1440-1465) | Northern Renaissance | Netherlandish painter (Haarlem) |
| OUWATER, Isaak | (1750-1793) | Rococo | Dutch painter (Amsterdam) |
| OVENS, Jürgen | (1623-1678) | Baroque | German painter |
| OVERBECK, Friedrich | (1789-1869) | Romanticism | German painter |
| OVERBEKE, Adriaen van | (active 1508-1529) | Northern Renaissance | Flemish painter (Antwerp) |