Artists O
| Sarah O' Brien | harp |
| Jürgen Ochs | tenor |
| Offenbacher Kammerorchester | orchestra |
| John Ogdon | piano |
| Jimin Oh-Havenith | piano |
| Opernchor des Deutschen Nationaltheaters Weimar | choir |
| Oratorienchor Karlsruhe an der Christuskirche | choir |
| Orchester der Städtischen Oper Berlin | orchestra |
| Orchestre de la Suisse Romande | orchestra |
| Orchestre Philharmonique de la RTF | orchestra |
| Orchestre philharmonique de Strasbourg | orchestra |
| Eugene Ormandy | conductor |
| Ósk Óskarsdóttir | tenor |
| fr. Sebastian M. Ostmeyer OP | tenor |
| Stefan Otters | timpani |
| Lisa Otto | soprano |