| Call Sign | Name |
|---|---|
| G3LP | Norman F. O'Brien |
| K1LCQ | Joseph F. O'Brien |
| N2PKP | Paige M. O'Brien |
| W8WVL | Thomas E. O'Bryan |
| AE4AV | Michael M. O'Byrne |
| W9WU | James C. O'Connell |
| KD4WST | John F. O'Connor |
| WA2DMK | Ione O'Donnell |
| N1EY | William H. O'Hara |
| WA2OPY | Janice O'Hara |
| WA3KYW | William V. O'Hara |
| AD4XX | James C. O'Hern |
| K4LTA | Bill O'Kain |
| K2KAU | James B. O'Keefe |
| KA7MUL | Michael O'Marah |
| EA5XX | Julio Volpe O'Neil |
| N3GO | Gary O'Neil |
| AG9A | Mark G. Obermann |
| WB2TTY | Stanley L. Obritski |
| F6CQU | Daniel Obry |
| K3UR | John D. Occhipinti |
| JA3HUL | Hideaki Ochi |
| W3DCR | Lewis C. Ockenhouse |
| N9CO | Charles C. Ocker |
| WB9TBT | Glen C. Odegard |
| W2RWE | Edwin F. Odell |
| W5GKH | Charles R. Ogilvie |
| JA1ELL | Seiji Okada |
| W6GRF | George Oku |
| KØZK | Arnold F. Olean |
| WB2HLY | Tom Olin |
| K2AV | Guy Olinger |
| K2UO | George Oliva, Jr. |
| K6UU | John A. Oliver |
| F6AFA | Andre Olivier |
| W6HAW | Irving E. Olsen |
| KØTO | Tod Olson |
| WØYXO | Kenneth A. Olson |
| W9YZG | Gary C. Olson |
| KB1JL | Eric R. Olsson |
| KI6MAH | Paige A. Omoto |
| JA1NUT | Shin Onisawa |
| JA7CEK | Mitsuo Onishi |
| JA1SY | Jun Onoda |
| JAØAFD | Toshihiko Oohira |
| PAØINA | Frans Oosthoek |
| WØRLI | Hank Oredson |
| W5OXA | Ernest E. Orman, Jr. |
| WB2YYB | Marc W. Ornstein |
| I1NU | Roberto Ortensio |
| AD6DK | Julio L. Ortiz |
| K2DO | Diane P. Ortiz |
| KN9P | Michael T. Ortlieb |
| KW1U | Marcia K. Osborn |
| K4LRL | Billy S. Osborne |
| W7WHY | Thomas K. Osborne |
| SP6AAT | Jan Osowski |
| N9BX | Bruce M. Osterberg |
| SM4KL | Karl O. Osterberg |
| W6XP | Stanley R. Ostrom |
| N2NA | Richard J. Ostrowski |
| K2UL | Dan Ostroy |
| KØMSR | Lavern A. Oszman |
| WD5BJT | Charles H. Otnott, III |
| W2FD | Gerald A. Otteni |
| 9J2BO | Brian Otter |
| LA5HE | Ragnar Otterstad |
| WD8OCV | Donald F. Otto |
| K5DPG | Al Oubre |
| OK1RP | Petr Ourednik |
| N6NB | Wayne Overbeck |
| AK4G | Elbert L. Owen |
| K5KV | Benson J. Owens |
| KT5Z | William H. Owens |
| W4DEC | Lawrence T. Owens |