| Name | Roles |
|---|---|
| O'Hara, Maureen | Performer (3) |
| O'Hara, Paige | Performer (27) |
| O'Hara, Riggs | Performer (4) |
| O'Hara, Stephanie, AKA Harajuku | Performer (9) |
| O'Hara, Steve | Performer (2) |
| O'Hare, Denis | Performer (4) |
| O'Hare, Evan | Performer |
| O'Hare, Michael | Performer |
| O'Haughey, M. | Performer |
| O'Haughey, Michael | Performer |
| O'Hea, Brendan | Performer (3) |
| O'Hennessy, Ross | Performer |
| O'Horgan, Tom | Music, Book, Performer |
| O'Hurley, John | Performer (2) |
| O'Jays, The | Performer |
| O'Keefe, Joani | Performer |
| O'Keefe, John | Conductor, Performer |
| O'Keefe, Laurence | Music (7), Lyrics (5), Conductor, Dance_Music, Vocal_Arrangements |
| O'Keefe, Markam | Performer |
| O'Keefe, Paul | Performer (3) |
| O'Keefe, Walter | Performer |
| O'Kelly, Fergus | Performer (2) |
| O'Kun, Lan | Music, Lyrics |
| O'Leary, Christen | Performer (3) |
| O'Leary, Dan | Producer (42), Liner_Notes (3) |
| O'Leary, Kelly | Performer |
| O'Leary, Richard | Performer |
| O'Leary, Tom | Performer (4) |
| O'Loughlin, Bernard | Performer |
| O'Malley, Brian | Performer |
| O'Malley, Brynn | Performer (3) |
| O'Malley, J. Pat | Performer (7) |
| O'Malley, Kerry | Performer (8) |
| O'Malley, Mark | Performer (3) |
| O'Malley, Muriel | Performer (5) |
| O'Malley, Owen | Performer |
| O'Malley, Pat | Performer (7) |
| O'Malley, Regina | Performer |
| O'Malley, Rory | Performer (4) |
| O'Malley, Thomas | Lyrics |
| O'Malley, Tony | Producer (2) |
| O'Mara, Terry | Performer |
| O'May, John | Book, Performer (8) |
| O'May, Pat | Performer |
| O'Neal Jr., George E. | Music, Lyrics, Music_Director, Performer |
| O'Neal, Charles | Book |
| O'Neal, Frederick | Performer |
| O'Neal, Hank | Producer, Liner_Notes |
| O'Neal, Jamie | Performer |
| O'Neal, Johnny | Conductor |