| Name | Roles |
|---|
| Orchestra, RKO Radio | Performer |
| Orchestra, RKO Studio | Performer |
| Orchestra, Robert Trendler | Performer |
| Orchestra, Royal Engineers | Performer |
| Orchestra, Royal Opera | Performer |
| Orchestra, Royal Promenade | Performer |
| Orchestra, RTE Concert | Performer |
| Orchestra, RTVE Symphony | Performer |
| Orchestra, Silver Screen | Performer |
| Orchestra, Slovak Philharmonic | Performer |
| Orchestra, Sound Stage | Performer |
| Orchestra, Starlight Symphony | Performer (2) |
| Orchestra, Syd Lawrence | Performer |
| Orchestra, Tony Osborne | Conductor |
| Orchestra, Ulster | Performer |
| Orchestra, Utah Symphony | Performer |
| Orchestra, Victor | Performer (3) |
| Orchestra, Victor Symphony | Performer (2) |
| Orchestra, Warner Bros. | Performer (2) |
| Orchestra, Westminster Symphony | Performer |
| Orchestra, Xalapa Symphony | Performer |
| Orchestre et Choeurs du Capitole de Toulouse | Performer (2) |
| Orchin, Karen | Performer (2) |
| Orci, Ramiro | Performer |
| Ordell, Darryl | Performer |
| Ordenneau, Vincent | Performer |
| Order, Jeff | Producer |
| Ordinas, David | Performer |
| Ordinola, Cesar | Performer (2) |
| Ordóñez, Jaime | Performer |
| Ordonneau, Maurice | Lyrics, Book |
| Orea, Guillermo | Performer (2) |
| Oreily, Alan | Performer |
| Orella, Francesc | Performer |
| Oremus, Stephen | Orchestrations (4), Conductor (6), Music_Director (3), Vocal_Arrangements (2), Producer, Performer |
| Oren, Dalia | Performer |
| Orenstein, Debbie | Music, Lyrics, Performer |
| Orenstein, Harriet | Performer |
| Orenstein, John | Music, Lyrics, Performer |
| Oreskes, Daniel | Performer |
| Orezzoli, Héctor | Book (2) |
| Orfaly, Alexander | Performer (4) |
| Orfeh | Performer (7) |
| Orfeo, Camerata | Performer |
| Orfgen, Samy | Performer |
| Orgambide, Pedro | Lyrics, Book |
| Oria, Elena | Translation |
| Oribemanolo, Alejandro | Lyrics |
| Orich, Steve | Orchestrations (8), Conductor (2) |
| Orich, Steven | Orchestrations (3), Conductor |
