Directory of Phobias - O
| Objects at the right side of the body | Dextrophobia |
| Odours | Osmophobia |
| Odours (body) | Osphresiophobia |
| Old people | Gerontophobia |
| Oneself | Autophobia |
| One thing | Monophobia |
| Open spaces | Agoraphobia or Kenophobia |
| Open high places | Aeroacrophobia |
| Operations | Tomophobia |
| Opinions | Allodoxaphobia |
| Opposite sex | Heterophobia |
| Otters | Lutraphobia |
| Outer space | Spacephobia |
| Overworking | Ponophobia |