| Name | Group | Language of Origin | Languages of Use | Meaning/Translation or Related Words | US 2021 |
|---|
| Oaklee | Oakley | Old English | English | oak field | #486 |
| Oakleigh | Oakley | Old English | English | oak field | #609 |
| Oakley | Oakley | Old English | English | oak field | #193 |
| Oaklyn | Oakley | Old English | English | oak field | #572 |
| Oaklynn | Oakley | Old English | English | oak field | #204 |
| Ocean | Ocean | English | English | ocean | #874 |
| Oceana | Oceane | French | English | Words: ocean | |
| Océane | Oceane | French | French | Words: ocean | |
| Octavia | Octavius/Octavia | Latin | German, English | the eighth, born in the eighth month | #248 |
| Oda | Otto/Ute | Old High German | German, Scandinavian | Words: wealth | |
| Odalis | Ottilia | Old High German | English | Words: wealth | |
| Odalys | Ottilia | Old High German | Spanish | Words: wealth | |
| Odelia | Ottilia | Old High German | English | Words: wealth | |
| Odeta | Odeta | Albanian | Albanian | Words: blue, sea | |
| Odett | Otto/Ute | Old High German | Hungarian | Words: wealth | |
| Odette | Otto/Ute | Old High German | French | Words: wealth | |
| Odilia | Ottilia | Old High German | German | Words: wealth | |
| Odilie | Ottilia | Old High German | German | Words: wealth | |
| Odina | Otto/Ute | Old High German | German | Words: wealth | |
| Odine | Otto/Ute | Old High German | German | Words: wealth | |
| Odrija | Edeltraud | Old High German | Latvian | Words: noble, honorable / strength, power | |
| Ofelia | Ophelia | Old Greek | Spanish | Words: help | |
| Oksana | Xenia | Old Greek | Russian | hospitality | |
| Oktavia | Octavius/Octavia | Latin | German | the eighth, born in the eighth month | |
| Okuhle | Okuhle | Zulu | Zulu | the good one | |
| Olalla | Eulalio/Eulalia | Old Greek | Spanish | to talk well | |
| Olava | Olaf/Olava | Old Norse | Scandinavian | ancestor's descendant | |
| Olea | Olea | Scandinavian | Scandinavian | | |
| Olesja | Alesya | Unknown | Slavic | | |
| Olesya | Alesya | Unknown | Russian | | |
| Olga | Helge/Helga | Old Norse | Russian | holy, blessed | |
| Olimpia | Olympia | Old Greek | Italian | | |
| Oline | Oline | Scandinavian | Scandinavian | | |
| Oliva | Olivia | Latin | Italian | the olive tree, the olive | |
| Olive | Olivia | Latin | French, English | the olive tree, the olive | #182 |
| Olivera | Olivera | Unknown | German | | |
| Olivet | Olivia | Latin | English | the olive tree, the olive | |
| Olivia | Olivia | Latin | German, English | the olive tree, the olive | #1 |
| Olívia | Olivia | Latin | Portuguese | the olive tree, the olive | |
| Olivija | Olivia | Latin | Slovenian | the olive tree, the olive | |
| Oliwia | Olivia | Latin | Polish | the olive tree, the olive | |
| Ólöf | Ólöf | Old Norse | Icelandic | | |
| Olympe | Olympia | Old Greek | French | | |
| Olympia | Olympia | Old Greek | German | | |
| Ombeline | Ombeline | Latin | French | Words: shadow | |
| Ombretta | Ombretta | Italian | Italian | | |
| Omphile | Omphile | Sesotho | Sesotho | maybe given | |
| Ona | Anna | Hebrew | Lithuanian | He (God) was gracious | |
| Onalerona | Onalerona | Unknown | English | maybe God is with us | |
| Onorata | Honoré/Honorée | Latin | Italian | Words: honor | |
| Onorina | Honoré/Honorée | Latin | Italian | Words: honor | |
| Oona | Une | Old Norse | Finnish | Words: be satisfied, be happy | |
| Opal | Opal | English | English | | #547 |
| Ophelia | Ophelia | Old Greek | German, English | Words: help | #321 |
| Ophélie | Ophelia | Old Greek | French | Words: help | |
| Orane | Orane | Arabic | French, Arabic | from Oran | |
| Orélie | Aurel/Aurelia | Latin | French | Words: golden | |
| Orestilla | Oreste/Orestina | Old Greek | Italian | | |
| Orestina | Oreste/Orestina | Old Greek | Italian | | |
| Oria | Oria | Latin | Italian | the golden | |
| Oriana | Oriana | Old French | Italian, English | Words: gold | |
| Oriane | Oriana | Old French | French | Words: gold | |
| Orianne | Oriana | Old French | French | Words: gold | |
| Orietta | Oria | Latin | Italian | the golden | |
| Orinda | Orinda | Unknown | English | | |
| Orla | Orla | Old Irish | English, Irish | golden princess | |
| Orlagh | Orla | Old Irish | Irish | golden princess | |
| Orlaith | Orla | Old Irish | Irish | golden princess | |
| Orlanda | Roland/Rolanda | Old High German | Spanish, Italian | Words: fame / land, homeland | |
| Orlane | Roland/Rolanda | Old High German | French | Words: fame / land, homeland | |
| Ornella | Ornella | Italian | German, Italian | Words: ash | |
| Orsola | Ursula | Latin | Italian | little bear | |
| Orsolya | Ursula | Latin | Hungarian | little bear | |
| Ortensia | Ortensio/Hortensia | Latin | Italian | | |
| Ortraud | Ortraud | Old High German | German | Words: strength, power | |
| Ortrud | Ortraud | Old High German | German | Words: strength, power | |
| Ortrun | Ortrun | Old High German | German | Words: secret, secret sign, rune | |
| Orvokki | Orvokki | Finnish | Finnish | violet, pansy | |
| Ostara | Ostara | Old High German | German | Words: Easter | |
| Ota | Ota | Unknown | | | |
| Othilie | Ottilia | Old High German | French | Words: wealth | |
| Ottavia | Octavius/Octavia | Latin | Italian | the eighth, born in the eighth month | |
| Ottaviana | Octavius/Octavia | Latin | Italian | the eighth, born in the eighth month | |
| Ottilia | Ottilia | Old High German | German, Latinized | Words: wealth | |
| Ottilie | Ottilia | Old High German | German | Words: wealth | |
| Ouafa | Ouafa | Unknown | Arabic | | |
| Ouarda | Warda | Arabic | French, Arabic | rose | |
| Oxana | Xenia | Old Greek | Russian | hospitality | |
| Öykü | Öykü | Turkish | Turkish | story | |
| Özge | Özge | Turkish | Turkish | | |
| Özlem | Özlem | Turkish | Turkish | longing | |
