- O'Brien, Linda
- O'Brien, Patricia
- O'Casey, Breon
- O'Connell, Steve
- O'Connor, John
- O'Connor, Eoin
- O'Connor, David
- O'Farrell, Alison
- O'Flannery, Jill
- O'Hagan, Desmond
- O'Hea, Claire
- O'Keeffe, Georgia
- O'Malley, Cathal
- O'Mara, James
- O'Neil, Henry Nelson
- O'Neil, Henry
- O'Neill, Martin
- O'Neill, Hugh
- O'Neill, George Bernard
- O'Shea, Christopher
- O'Toole, Tim
- O'Toole, Nancy
- O'Toole, Michael
- O'Very Covey, Traci
- Oakley, Jo
- Oakley, H.
- Obadia, Dominique
- Obata, Chiura
- Oberhausen, Emmanuel
- Oborn, Anne Marie
- Ochocki, Gregory T.
- Ochtervelt, Jacob
- OConnor, Elizabeth
- OConnor, Dawn
- Odazzi, Giovanni
- Odowski, A.
- Oeder, Georg Christian
- Offenbach, John
- Ofili, Chris
- Ogawa, Toshu
- Ogawa, Sashichi
- Oglivie, Peter
- Ogunshuyi, Maggi
- Ohland, Christa
- Ohlsson, Ewa
- Okano, Ryuichi
- Okre
- Olagnon, Pierre Victor
- Olalla, Francisco Garcia Santa
- Oldach
- Oldenburg, Claes
- Oldridge, David
- Olitski, Jules
- Olivain, Claire
- Oliver, William
- Oliver, Jenny
- Oliver, Peter
- Oliver, Bunny
- Olivier, Michel Barthelemy
- Olivier, Charmaine
- Oller, Francisco
- Oller, Erika
- Ollivierre, Lonnie
- Olsen, Barbara
- Olsen, Katy
- Olsen, Greg
- Olsky
- Olson, Scott
- Olsson, Margareta
- Olsufiev, Andre
- Olthof, Corry
- Olukman, Ayline
- Olympics Collection (IOC)
- Ona
- Onderdonk, Julian
- Onslow, Edouard Amable
- Opie, Julian
- Opie, John
- Opitz, Georg Emanuel
- Oppler, Ernest
- Optendrees, Liesbet
- Oram, Ann
- Orazi, Manuel
- Orchardson, Sir William Quiller
- Ord, Brenda
- Oremek, Rosita
- Orkin, Ruth
- Orlovskii, Aleksandr Osipovich
- Orlovskii, Vladimir Donatovich
- Orme, Warwick
- Orme, Edward
- Ormerod, Clare
- Orndorf, David
- Orpen, Sir William
- Orr, Maya
- Orsborn, Nick
- Orsman, Gill
- Ortega, Guillaume
- Ortega, Martin Rico Y
- Ortelius, Abraham
- Ortenstone, Nancy
- Orth, H.
- Ortubia, P.
- Orzelowski, Marek
- Os, Georgius Jacobus Johannes Van
- Osaka, Kaigyokusai Masatsugu Of
- Osbjorn, Susan
- Osborne, Walter Frederick
- Osborne, Christopher
- Osbourne, Richard
- Osias the Elder, Beert
- Osslund, Helmer
- Ostlund, Leif
- Ota, Masao
- Otero, Mariano
- Ott, Bernard
- Ottesen, Otto Diderich
- Ottewell, Guy
- Otto, Renate
- Oud, Jacobus J.P.
- Oudkerk, Marie Louise
- Oudry, Jacques Charles
- Oudry, Jean-Baptiste
- Ouless, William Walter
- Ouseley, William Gore
- Outeiral, Nuria
- Outin, Pierre
- Ouwerkerk, Erik Jan
- Owadally, Hanna
- Owen, G
- Owen, William
- Owen, Wayde
- Owen, Tjasa
- O´Klein, Boris
