| Oleśnica | Oleśnica |
| Olešnice | Olešnice |
| Olga | Olga |
| Olga Aleksandrowna Romanowa | Grand Duchess Olga Alexandrovna of Russia |
| Olga Aleksandrówna Romanowa Kulikowska | Grand Duchess Olga Alexandrovna of Russia |
| Olga Bryzgina | Olga Bryzgina |
| Olga Connolly | Olga Fikotová |
| Olga Fiodorowna | Olga Feodorovna of Baden |
| Olga Gyarmati | Olga Gyarmati |
| Olga Kaniskina | Olga Kaniskina |
| Olga Karnowicz | Olga Valerianovna Paley |
| Olga Kijowska | Olga of Kiev |
| Olga Knipper | Olga Knipper |
| Olga Konstantinowna Romanowa | Olga Konstantinovna of Russia |
| Olga Kotlarowa | Olga Kotlyarova |
| Olga Kuzienkowa | Olga Kuzenkova |
| Olga Morozowa | Olga Morozova |
| Olga Nikołajewna Romanowa | Grand Duchess Olga Nikolaevna of Russia |
| Olga Puczkowa | Olga Poutchkova |
| Olga Pyliewa | Olga Pyleva |
| Olga Riabinkina | Olga Ryabinkina |
| Olga Romanowa | Grand Duchess Olga Nikolaevna of Russia |
| Olga Rubcowa | Olga Rubtsova |
| Olga Sawczuk | Olga Savchuk |
| Olga Zajcewa | Olga Zaitseva |
| Olga Zawiałowa | Olga Zavyalova |
| Olga Żarkowa | Olga Jarkova |
| Olgiate Comasco | Olgiate Comasco |
| Olgierd | Algirdas |
| Olgierd Giedyminowic | Algirdas |
| Olha Kobylańska | Olha Kobylyanska |
| Olhão da Restauração | Olhão |
| Olibriusz | Olybrius |
| Oliena | Oliena |
| oligarchia | oligarchy |
| Oligocen | Oligocene |
| Oligomery | Oligomer |
| Oligonukleotydy | Oligonucleotide |
| oligopol | oligopoly |
| Olimp | Mount Olympus |
| Olimpi Rustavi | FC Olimpi Rustavi |
| Olimpia | Olympia |
| Olimpia Asunción | Olimpia Asunción |
| Olimpia de Gouges | Olympe de Gouges |
| Olimpia Mancini | Olympia Mancini |
| Olimpia Tegucigalpa | Club Deportivo Olimpia |
| Olimpiada Iwanowa | Olimpiada Ivanova |
| Olimpiada Machabejska | Maccabiah Games |
| Olimpiada Specjalna | Special Olympics |
| Olimpiada szachowa | Chess Olympiad |
| Olimpias | Olympias |
| Olimpiejon | Temple of Olympian Zeus |
| Olimpija Lublana | HDD Olimpija Ljubljana |
| Olimpijka | Olimpijka |
| olimpijski | olimpic |
| Olimpijski Konkurs Sztuki i Literatury | Art competitions at the Olympic Games |
| Olimpo Bahía Blanca | Olimpo de Bahía Blanca |
| Olimps Ryga | JFK Olimps Rīga |
| Olinda | Olinda |
| Olinek Okrąglinek | Rolie Polie Olie |
| Olingo | Olingo |
| Olint | Olynthus |
| Olita | Alytus |
