| O.P.E.P. | OPEC |
| O.T.A.N. | OTAN |
| Oahu | Oahu |
| OAK | Oak |
| Oak Brook | Oak Brook |
| Oak Park | Oak Park |
| Oak Ridge | Oak Ridge |
| Oakland | Oakland |
| Oakville | Oakville |
| oasis | oásis |
| Oaxaca | Oaxaca de Juárez |
| Oaxaca de Juárez | Oaxaca de Juárez |
| Ob | Rio Ob |
| Obala | Obala |
| Obama | Obama |
| Oban | Oban |
| Obanazawa | Obanazawa |
| Obduction | Obducção |
| Obdulio Varela | Obdulio Jacinto Varela |
| Obdurodon dicksoni | Obdurodon dicksoni |
| Oben am jungen Rhein | Hino nacional do Liechtenstein |
| Oberbalm | Oberbalm |
| Oberbüren | Oberbüren |
| Oberdorf | Oberdorf |
| Oberegg | Oberegg |
| Oberembrach | Oberembrach |
| Oberems | Oberems |
| Oberengstringen | Oberengstringen |
| Oberentfelden | Oberentfelden |
| Obergesteln | Obergesteln |
| Obergösgen | Obergösgen |
| Oberhallau | Oberhallau |
| Oberhausen | Oberhausen |
| Oberhelfenschwil | Oberhelfenschwil |
| Oberhofen | Oberhofen am Thunersee |
| Oberhofen am Thunersee | Oberhofen am Thunersee |
| Oberiberg | Oberiberg |
| Oberkirch | Oberkirch |
| Oberkommando der Wehrmacht | Oberkommando der Wehrmacht |
| Oberkulm | Oberkulm |
| Oberlangenegg | Oberlangenegg |
| Oberlin | Oberlin |
| Oberlunkhofen | Oberlunkhofen |
| Oberndorf am Neckar | Oberndorf |
| Oberon | Oberon |
| Oberried am Brienzersee | Oberried am Brienzersee |
| Oberrieden | Oberrieden |
| Oberriet | Oberriet |
| Oberrohrdorf | Oberrohrdorf |
| Oberrüti | Oberrüti |
| Oberrœdern | Oberroedern |
| Obersaxen | Obersaxen |
| Obersiggenthal | Obersiggenthal |
| Oberstenfeld | Oberstenfeld |
| Oberstgruppenführer | Patentes da SS |
| Oberstocken | Oberstocken |
| Oberurnen | Oberurnen |
| Oberuzwil | Oberuzwil |
| Oberwal d | Oberwald |
| Oberwald | Oberwald |
| Oberwil | Oberwil im Simmental |
| Oberwil im Simmental | Oberwil im Simmental |
| Oberwil-Lieli | Oberwil-Lieli |
| Oberägeri | Oberägeri |
| Obfelden | Obfelden |
| Obi-Wan Kenobi | Obi-Wan Kenobi |
| Obihiro | Obihiro |
| Obilic Belgrade | Obilić |
| Obina | Manuel de Brito Filho |
| Obj | OBJ |
| Object Constraint Language | OCL |
| Object Linking and Embedding | Object Linking and Embedding |
| Object Management Group | Object Management Group |
| Object Modeling Technique | Object-modeling technique |
| Object-relational mapping | ORM |
| objecter | objetar |
| objecteur de conscience | pacifista |
| objectif | meta |
