| OAKEY m ? |
| OAKLEE f Canada |
| OAKLEY m English |
| OAKLEY f & m English |
| OAKTREE m & f Indian |
| OASIS f English |
| OATIS m & f African |
| OATIS m Irish, Greek, German |
| OBADA m Arabic |
| OBAD-HAI m Celtic Mythology |
| OBAMA m ? |
| OBAMA m English? |
| OBANDO m & f Colombia |
| ÖBEAU m French, German |
| OBEDIENCE f English (Archaic) |
| OBERGE m German |
| OBIANUJU f Igbo |
| OBICHUKWU m Igbo, Nigerian |
| OBINNA m Igbo, Nigerian |
| OBINNA m Igbo |
| OBI-WAN m Popular Culture |
| OBI-WAN m ? |
| OBORO m & f Japanese |
| OBSIDIAN m ? |
| OBUCHUKWUNEME f & m African |
| OCALLA f ? |
| OCCY m ? |
| OCEANA f English |
| OCEANICA f French |
| OCEANNA f Romanian |
| OCEEN f ? |
| OCINE f English |
| OCTAAF m Dutch |
| OCTAV m Romanian |
| OCTAVE m French |
| OCTAVIÀ m Catalan |
| OCTAVIAAN m Dutch |
| OCTAVIANA f Ancient Roman, Spanish |
| OCTAVIANO m Spanish |
| OCTAVIE f French |
| OCTAVIEN m French |
| OCTAVIENNE f French |
| OCTÁVIO m Portuguese |
| OCTOBER f English |
| OCTOBER f ? |
| OCTOBER m & f English |
| OCTOBER f English |
| O'DANIEL m Irish |
| ODAS m ? |
| ODDBJØRG f Norwegian |
| ODDSNIFFER m English |
| ODDVEIG f Norwegian |
| ODELIA f Israeli |
| ODELIA f Hebrew |
| ODELYS f Spanish |
| ODERA f Hebrew |
| ODESIA f Portuguese |
| ODFRID m Ancient Germanic |
| ODGER m Ancient Germanic, German |
| ODIE m & f ? |
| ODÍN m Galician, Spanish |
| ODINA f Norwegian |
| ODINAKACHUKWU m & f African |
| ODINO m Italian |
| ODISEJ m Bosnian, Croatian |
| ODISEO m Galician, Spanish |
| ODISSEO m Italian |
| ODISSEU m Catalan, Portuguese |
| ODMAR m Ancient Germanic, Dutch |
| ODOMAR m Ancient Germanic |
| ODOMIR m Ancient Germanic |
| ODRIS f German, Swiss |
| ODULF m Ancient Germanic, Dutch, German |
| ODUOR m Luo, Kenyan, African |
| ODWIN m Ancient Germanic |
| ODYN m Polish |
| ODYSEUSZ m Polish |
| OEDOAIA f ? |
| OEIN m Irish |
| OELLA f American, English |
| OENICKA f Dutch |
| OERTA f Albanian |
| OET m Frisian |
| OETSE m Frisian |
| OETSINA f Frisian |
| OETSKE f Frisian |
| OFAEBIA f African |
| OFANIA f & m Pacific/Polynesian |
| OFELIAH f American |
| OFELIAH f Biblical |
| OFFE m Frisian |
| OFFERT m Frisian |
| OFURE m & f African, Esan, Nigerian |
| OGBWENA f ? |
| OGHENEGARE m Urohobo, Nigerian |
| OGIER m Dutch, French |
| OGUZ m Turkish |
| OHASUKILIKIOMO m & f Irish Mythology |
| OHIO m ? |
| OHLAINE f Various |
| OHLAN m & f Various |
| OHLANE f & m Various |
| OHLAYNE f Unknown |
| OHRIM m Ukrainian |
| OIDHCHE m Scottish |
| OILIBHÉAR m Irish |
| OILIBHÉAR m Irish |
| OINDRILLA f Indian |
| OJAS m Indian |
| OJO m African, Yoruba |
| OJO f & m English |
| OJONUBI f & m African |
| OK m & f Korean |
| OKAMI f & m Japanese |
| OKAMI m & f Japanese |
| OKE m German, Frisian |
| OKEEMA f Native American |
| OKENNA m Igbo |
| OKERLAND m & f ? |
| OKEY f Indian |
| OKI f Japanese |
| OKI m Native American, Inuit |
| OKKULIINA f Finnish |
| OKLARINE f ? |
| ÖKLID m Turkish |
| OKTAVIA f German |
| OKTAVIJAN m Croatian |
| OKTAVIJE m Bosnian, Croatian, Serbian |
| OKTAWIA f Polish |
| OKTAWIUSZ m Polish |
| OKTOBER f & m English |
| OLADEPE f African, Yoruba |
| OLADUNNI m African |
| OLAGUE m & f Basque |
| OLANA f ? |
| OLANA f Popular Culture |
| OLANDER m ? |
| OLANE f Various |
| OLARICHE f African |
| OLATAYO m & f African |
| OLATZ f Basque |
| OLAUG f Norwegian |
| OLAVA f Norwegian, Swedish |
| OLAVE f & m European |
| OLAWALE m & f Yoruba |
| OLAYA f Spanish |
| OLEANDER f & m English |
| OLEN m Swedish |
| OLENKA f Ukrainian |
| OLESIA f Ukrainian |
| OLESJA f Belarusian, Russian |
| OLESYA f Russian |
| OLEXANDER m Ukrainian |
| OLEYSA f English, Russian |
| OLEZIDA f French Louisiana |
| OLGA f Russian |
| OLIANNA f Hawaiian |
| OLIDAMMARA m Celtic Mythology |
| OLIE m English |
| OLIER m Breton |
| OLIMP m Catalan, Croatian, Polish |
| OLIMPIADA f Russian |
| OLIMPIODORO m Italian, Spanish |
| OLIMPO m Italian, Spanish, Portuguese |
| OLIN m English |
| OLINA f Danish |
| OLINDA f German, Spanish |
| OLINDO m Italian |
| OLINE f Danish, Norwegian, Greenlandic |
| OLINE f Norwegian |
| OLIPRIYA f Indian (Bengali) |
| OLISA m African |
| OLISAEMEKA m African |
| OLISHA f ? |
| OLIVANE f French |
| OLIVERA f Serbian, Croatian |
| OLIVIACIA f ? |
| OLIVIANNE f English, ? |
| OLIVIERO m Italian |
| OLIVINE f English |
| OLIZA f ? |
| OLLY m English |
| ÓLÖF f Icelandic |
| ÓLÖF f Icelandic |
| OLOSSA f ? |
| OLPOPPY f American |
| OLSI m Albanian |
| OLUF m Norwegian |
| OLUWAKEMI f African |
| OLUWAKEMI f Yoruba |
| OLUWANIFESIMI m & f Yoruba |
| OLUWARANTI f & m Yoruba |
| OLUWASEYANU m & f African |
| OLUWASOLA f & m African, West Africa, Nigerian, Yoruba |
| OLUWATOBILOBA f & m Nigerian, Yoroba |
| OLUWATOSIN m & f Yoruba |
| OLVIANIE f ? |
| OLY f & m Norwegian |
| OLYMPIODORE m French |
| OLYMPIODORUS m Ancient Greek (Latinized) |
| OLYMPUS m Ancient Greek (Latinized) |
| OMAH m Trinidadian |
| OMAIR m Arabic |
| OMAKA f Maori |
| OMALLEY m & f Ancient Egyptian |
| OMARI m American |
| OMARI m African, Arabic, Hebrew |
| OMAYRA f Spanish |
| OMBELINE f French |
| OMBRETTA f Italian |
| OMELIA f English |
| OMEN f & m ? |
| OMENANKUKKA f Finnish |
| OMERO m Italian |
| OMJIT m Hindu Mythology |
| OMKUMAR m Indian, ? |
| OMMOIS m ? |
| OMNI m Mormon, English |
| OMNI f & m English, Mormon |
| OMNIA f Popular Culture |
| OMNYA f Egyptian Mythology |
| OMOGBAI m African |
| OMOJAYOGBE m Yoruba |
| OMOLAYO f Yoruba |
| OMONDI m Luo, Kenyan, African |
| OMONDI m African |
| OMONIKE f African |
| ONAONA f Hawaiian |
| ONARAI f American, ? |
| ONAT m Turkish |
| ONAWA f Native American |
| ONDINA f Italian |
| ONDINE f Latin |
| ÖNDÓTT f Ancient Scandinavian |
| ONEAL m English, ? |
| ONERVA f Finnish |
| ONESÍFORO m Spanish |
| ONESIFORO m Italian |
| ONÉSIMO m Spanish, Portuguese |
| ONESSA f English |
| ONIA f Native American |
| ONIAL m English |
| ONICA f Popular Culture |
| ONIDA f Native American |
| ONIE f ? |
| ONIGIUSZ m Polish |
| ONIGUMO m Japanese |
| ONIRIA f Spanish (Rare) |
| ONNA f Lithuanian |
| ONNA f Japanese |
| ONNE f ? |
| ONNEA f Finnish |
| ONNEA f Finnish |
| ONNIA f Finnish |
| ONNIKA f Russian, Ancient Scandinavian |
| ONNO m Dutch |
| ONNOR f ? |
| ONOMÁCRITO m Spanish |
| ONOMACRITUS m Ancient Greek (Latinized) |
| ONOMAKRITOS m Ancient Greek |
| ONORATA f Italian |
| ONORATO m Italian |
| ONORINA m & f Italian |
| ONORIO m Italian |
| ONSI m Popular Culture, ? |
| ONSLOW m Old English, German |
| ONTERIO m African |
| ONUFREY m Ukrainian |
| ONWAZ m ? |
| ONYEDIKACHI m & f Igbo, African |
| ONYEMECHI m & f African |
| ONYINAH m African |
| ONYINYECHUKWU f & m African |
| ONYSTE f English |
| ONYX m & f English, Latin, Greek |
| OPE m African |
| OPHÉA f French |
| OPHÉLIE f French |
| OPIE m Popular Culture |
| OPIRONY f & m Greek Mythology |
| OPIS f Ancient Roman |
| OPRED m African, Hungarian, Icelandic, Turkish |
| OPTATUS m ? |
| OPTIUS m ? |
| OR f & m Israeli, Jewish |
| ORABELLA f Esperanto |
| ØRÆÐ f ? |
| ORALVA f Spanish |
| ORANGE f ? |
| ORANGEJELLO m & f English |
| ORANGEJELLO m & f Southern United States |
| ORARAT f Thai |
| ORAZIA f Italian |
| ORBIANA f Ancient Roman, History |
| ORBIANE f French |
| ORBIANUS m Ancient Roman |
| ORCHID f ?, English |
| ORCHID f English, Greek |
| ORDIGLIONE m Italian |
| OREL f & m Israeli |
| OREN m & f Welsh |
| OREN m Biblical |
| ORENDA f Native American, Iroquois |
| ORENTHAL m ? |
| OREOLUWA m & f Yoruba |
| ORESTA f Greek, Lithuanian |
| ORESTE m Italian |
| ORETHY f English |
| ORFEJ m Croatian |
| ORFEU m Portuguese |
| ORFEUSZ m Polish |
| ORGETORIX m Ancient Celtic, History |
| ORGUEIL f French |
| ORHAN m Turkish |
| ORIEL m & f French |
| ORIEL f English, French |
| ORIELLA f Italian |
| ORIETTA f Italian |
| ORIGIN f English |
| ORIHIME f Japanese |
| ORIN m Celtic Mythology |
| ORINA f Finnish, Swedish |
| ORINO f Japanese |
| ORIOL m Catalan |
| ORIOL m Catalan |
| ORIUNDE f & m Moldovan, Romanian |
| ORIYA f Jewish |
| ORKIDE f Turkish, ? |
| ORKUT m Turkish |
| ORLAITHA f Irish |
| ORLAITHE f Ancient Celtic, Celtic Mythology, English, Scottish, Irish |
| ORLAN m English |
| ORLANA f Polish, Hebrew, ? |
| ORLANDO m Spanish |
| ORLANGEA f ? |
| ORLÉANS f & m Latin, French |
| ORLENA f Greek |
| ORLIN m ? |
| ORLITHEA f Irish Mythology, Irish |
| ORLPOPPY f American |
| ÖRN m Swedish |
| ORO f Jewish, Judeo-Spanish |
| OROCHIMARU m Japanese |
| OROCHIMARU m Japanese |
| OROMIS m Literature |
| ORORO f & m ? |
| ORORO f African |
| OROVIDA f Jewish, Judeo-Spanish |
| ORPHÉA f French |
| ORPHÉE m French |
| ORR m & f Irish |
| ORRI m Icelandic |
| ORRIS m English, Scottish |
| ORRIS m ? |
| ORSEIS f ? |
| ORSI f Hungarian |
| ORSOLINA f Italian |
| ORSY m Hebrew |
| ORTANSA f Romanian |
| ORTECA f ? |
| ORTEL m English |
| ORTENSIA f Italian |
| ORTENSIO m Italian |
| ORUÇ m Turkish |
| ORVIL m English |
| ORVIN m Norwegian |
| OSA f English |
| OSARETIN f & m African, Edo |
| OSBALDO m Spanish |
| OSDEN f & m Indian (Roman Catholic) |
| OSEAME m Italian |
| OSÉE m French |
| OSEI m & f African |
| OSEMAN m Hebrew |
| OSHEENA f Irish |
| OSHUN f African, Yoruba |
| OSIAN m Welsh Mythology, Welsh |
| OSIAN m Welsh, Welsh Mythology |
| OSITA m Igbo |
| OSITHE f French |
| OSITHE f French |
| OSKAN m ? |
| OSKAN m Anglo-Saxon Mythology |
| OSLA f & m Scottish |
| ÖSLEM f Turkish |
| OSMAR m Anglo-Saxon |
| OSMARLIN m Spanish |
| OSRIC m Ancient Germanic, English |
| OSROE m English |
| OSSI m Finnish |
| OSSIE m & f English |
| OSTAP m Ukrainian |
| OSTERMANN m German, ? |
| OSTILIANO m Italian |
| OSTILIO m Italian |
| OSTOJA m Serbian |
| OSVALDA f Spanish, Italian, Portuguese |
| OSWALDA f German, Polish |
| OSYTH f Anglo-Saxon, English |
| OT m Dutch |
| OTA f & m Danish, German, Czech |
| OTELLO m Italian |
| OTFRIED m Dutch, German |
| OTGER m German |
| OTHA m Armenian |
| OTHELIA f English |
| OTHELIUS m Norwegian |
| OTHELIUS m Norwegian |
| OTHILIE f Norwegian |
| OTIANU m African, German, Spanish, Portuguese |
| OTILIA f Romanian |
| OTMAR m Czech |
| OTMAR m German |
| OTT m Estonian |
| OTTAVIANA f Italian |
| OTTILIO m Italian |
| OTTONE m Italian |
| OTWIN m German |
| OTYLIA f Czech, German, Polish |
| OTYLIA f Czech, German, Polish |
| OUALID m Arabic |
| OUCH m ? |
| OUDOM m Khmer |
| OUMOU f African |
| OUTI f Finnish |
| OUTLAW m & f English |
| OUTRAGEOUS f ? |
| OUWE m Frisian |
| OVALIA f Greek, Spanish |
| OVEDA f Indian |
| OVELIA f Greek, Spanish |
| OVERTON m English |
| OVETTE f English |
| OVUNC m Turkish |
| OWURA m West-African |
| OYA f Turkish |
| OYERONKE f African |
| OZELL f Native American |
| OZELLA f English, ? |
| OZICHI m Igbo, African |
| OZICHI f Igbo |
| OZIOMA m & f Igbo |
| OZIY'AH f Irish Mythology |
| OZMA f Mythology |
| OZNY f Biblical |
| OZORA m Japanese |
| OZORO f African |
| OZREN m Bosnian, Croatian |
