Girl names that start with O run from favorites like Olivia, Olive, Ophelia and Opal to rare picks like Opaline, Ottoline and Ombeline, and this list of 147 gives a checked origin and meaning for every one.
O is a small letter for names, but a rich one. It holds the most popular girl name in the country (Olivia, No. 1 for babies born in 2025, according to the Social Security Administration), plus saints’ names, gemstone and flower names, and names from languages around the world.
We grouped these O girl names by style: classic, unique, short, long and vintage, nature, mythology and biblical, international and gender neutral. Then come the many sounds of O, nicknames, sibling and middle name ideas, and a quick initials check.
Key Takeaways
- Olivia is the only O name in the SSA top 10 for girls born in 2025, and it is No. 1.
- Familiar O names for girls include Olive, Ophelia, Octavia, Opal, Odette, Oriana, Oona and Orla.
- Rare options include Opaline, Orinda, Ottoline, Ombeline, Orsina and Orabela.
- O makes many first sounds: long O in Opal, AH in Olive, OO in Oona, W in Ouida, so check how each name is said.
- Test your favorite with the initials, say it out loud, spelling and nickname checks before you decide.
Table of Contents
Girl Names That Start With O at a Glance
Quick Answer
Every origin and meaning on this page was checked against the name’s own entry on Behind the Name in October 2026. Where the reference calls a meaning unknown, uncertain or possible, we say so.
Start with the best known baby girl names that start with O. For ideas beyond one letter, see our main list of baby girl names, or browse the next letter with girl names that start with P.
| Name | Origin | Meaning |
|---|---|---|
| Olivia | English, Italian, Spanish, French, German, Scandinavian and more | Used in this spelling by Shakespeare in Twelfth Night (1602); possibly based on Oliva or Oliver, or directly on Latin oliva, “olive” |
| Olive | English, French | From the English and French word for the olive tree, from Latin oliva |
| Ophelia | English, literature, Ancient Greek | From Greek opheleia: “help, advantage”; the tragic daughter of Polonius in Shakespeare’s Hamlet (1600) |
| Octavia | English, Spanish, Romanian, Ancient Roman | Feminine form of Octavius; Octavia was the sister of the Roman emperor Augustus |
| Opal | English | From the iridescent gemstone, the birthstone of October; the word goes back to Sanskrit upala, “jewel” |
| Odette | French | French diminutive of Oda or Odilia; the princess turned into a swan in Tchaikovsky’s ballet Swan Lake (1877) |
| Oriana | Italian, Spanish | Possibly from Latin aurum, “gold”, or Spanish oro or French or; a king’s daughter in the medieval legend of the knight Amadis |
| Odessa | Various | From the Ukrainian city on the Black Sea, named after the ancient Greek city Odessos, of uncertain meaning; also used as a feminine form of Odysseus |
| Olympia | Greek, Slovak | Feminine form of Olympos, a personal name taken from Mount Olympus, home of the Greek gods |
| Oona | Irish, Finnish | Anglicized form of Irish Úna, probably from Old Irish úan, “lamb”; also a Finnish form |
| Orla | Irish | Anglicized form of Órlaith: “golden ruler” |
| Olga | Russian, Polish, German, Scandinavian, Greek and many more | Russian form of the Old Norse name Helga; Saint Olga ruled Kievan Rus as regent in the 10th century |
| Odelia | English | Form of Odilia, from Old German elements meaning “heritage” or “wealth, fortune” |
| Ottilie | German | German form of Odilia |
| Oksana | Ukrainian, Russian | Ukrainian form of Xenia: “hospitality” in Greek |
| Olena | Ukrainian | Ukrainian form of Helen, probably from Greek helene, “torch” (possibly related to selene, “moon”) |
| Ofelia | Spanish, Italian | Spanish and Italian form of Ophelia |
| Ornella | Italian | Created by Gabriele d’Annunzio for his 1904 novel La Figlia di Jorio; from Tuscan ornello, “flowering ash tree” |
Olivia has an interesting story. Behind the Name notes that the name was rare in Shakespeare’s time and that he used this spelling for a noblewoman in Twelfth Night. The name has been used in the English-speaking world since the 18th century. Today it tops the Social Security Administration (SSA) list for girls born in the United States in 2025.
Four old names stand behind a large share of the O list. If you love one member of a family, try the others:
- The olive family: Olivia, Olive, Oliva, Oliwia and Olivette all connect to Latin oliva, “olive”, some directly and some through a masculine name whose own origin is uncertain.
- The Odilia family: Odilia, Odile, Odelia, Ottilie, Ottilia, Otilia, Otylia and Ottoline all trace back to an Old German name meaning “heritage” or “wealth, fortune”. Odette and Odete are diminutives of Oda or Odilia.
- The Ophelia family: Ophelia, Ofelia and Ophélie come from Greek opheleia, “help, advantage”.
- The golden names: Oriana, Oriane, Orianne, Oria, Orietta, Orinda and Orabela are tied, sometimes only possibly, to Latin aurum or Spanish oro, “gold”. Irish Órlaith (and its forms Orla and Orlagh) gets its “gold” from Old Irish ór.
Unique and Rare Girl Names That Start With O
Looking for unique girl names that start with O? Behind the Name marks several of these as rare in English, French, Italian, Romanian or Croatian, and none of them is common in the United States. Several are built from pieces you already know, such as Opal, Odette and Ottilie, which makes them easier to say than they look.
| Name | Origin | Meaning |
|---|---|---|
| Opaline | English (rare), French (rare) | Elaborated form of Opal; also an English and French word meaning “resembling an opal” |
| Orinda | English (rare) | Probably an elaboration of Spanish oro, “gold”; the pen name of the English poet Katherine Philips (1631 to 1664) |
| Odetta | English (rare) | Latinate form of Odette |
| Oralie | English (rare) | Possibly a variant of Aurélie, the French feminine form of Aurelius |
| Ottoline | English (rare) | Diminutive of Ottilie; borne by the British socialite Lady Ottoline Morrell (1873 to 1938) |
| Oria | Italian (rare) | Italian form of Aurea, a Latin name from aureus: “golden” |
| Orsina | Italian (rare) | Feminine form of Orsino, from the Roman name Ursinus (a derivative of Ursus, the Latin word for bear) |
| Ovidia | Ancient Roman, Spanish (rare), Romanian (rare) | Feminine form of Ovidius, the family name of the poet Ovid, possibly from Latin ovis, “a sheep” |
| Osanne | French (rare) | French form of Osanna, from the religious exclamation Hosanna: “deliver us” |
| Ombeline | French | Feminine form of Humbelin, a medieval diminutive of Humbert (“bear cub” plus “bright”); the Blessed Ombeline was the sister of Saint Bernard of Clairvaux |
| Obdulia | Spanish | Meaning unknown; the name of a saint from Toledo, Spain, whose life details are unknown |
| Orabela | Esperanto | “Golden-beautiful” in Esperanto, from Latin aurea, “gold”, and bella, “beautiful” |
| Ozana | Romanian (rare), Croatian (rare) | Romanian and Croatian form of Osanna |
Two honest notes. Obdulia’s meaning is unknown, and so are the details of the Spanish saint who bore it, so do not trust any site that gives it a confident translation. Orabela comes from Esperanto, the constructed language, which explains its neat “golden-beautiful” meaning.
To see how common a name is, use the Popularity of a Name search on the SSA baby names page. The SSA leaves out names with fewer than 5 occurrences to protect privacy, so the very rarest names will not show up at all. For more ideas, see our unique girl names guide.
Short O Names for Girls (3 to 4 Letters)
Short O names are easy to spell and pair well with a long surname or a long middle name. A surprising number come from Hebrew, where several build on or, the word for “light”.
| Name | Origin | Meaning |
|---|---|---|
| Ora | Hebrew | Strictly feminine form of Or: “light” in Hebrew |
| Orah | Hebrew | Alternate transcription of the Hebrew name Ora |
| Orli | Hebrew | “Light for me” in Hebrew |
| Orly | Hebrew | Alternate transcription of the Hebrew name Orli |
| Orit | Hebrew | “Light” in Hebrew |
| Oda | German, Norwegian, Germanic | Feminine form of Otto (“wealth, fortune”); the name of a semi-legendary 8th-century saint in Brabant |
| Ona | Catalan | Short form of Mariona (a Catalan diminutive of Maria); also matches a Catalan word for “wave” |
| Oana | Romanian | Romanian short form of Ioana, a feminine form of John |
| Olya | Russian, Ukrainian | Diminutive of Olga or Olha |
| Oili | Finnish | Finnish form of Olga |
| Outi | Finnish | Karelian Finnish form of Avdotya, the Russian form of Eudocia (“to be well pleased” in Greek) |
| Ola | Polish | Polish short form of Aleksandra |
Ora, Orah, Orli, Orly and Orit are a little cluster of light names: Ora is the strictly feminine form of the Hebrew name Or, “light”, and Orli means “light for me”. You will find more like them in our list of names that mean light. Other short choices sit elsewhere on this page: Opal, Olga, Oona, Orla, Orna, Ofra, Ori, Oni, Ofa and Ops.
Long, Elegant and Vintage O Names
Longer O names bring a formal feel and, often, a ready nickname. Many of them are the Italian, Swedish, Romanian or French forms of names from the tables above.
| Name | Origin | Meaning |
|---|---|---|
| Odilia | Germanic (Latinized) | From Old German uodil, “heritage”, or ot, “wealth, fortune”; Saint Odilia, an 8th-century nun, is the patron saint of Alsace |
| Odile | French | French form of Odilia |
| Ottavia | Italian | Italian form of Octavia |
| Orietta | Italian | Diminutive of Oria |
| Orsola | Italian | Italian form of Ursula: “little bear” in Latin |
| Osanna | Italian | Italian form of Hosanna; borne by a 15th-century Italian saint and a 16th-century Montenegrin saint |
| Olimpia | Italian, Spanish, Romanian, Polish (rare), Hungarian (rare) | Form of Olympias, a feminine form of Olympos |
| Ondina | Portuguese, Italian | Portuguese and Italian form of Undine, from Latin unda: “wave” |
| Ottilia | Swedish | Swedish form of Odilia |
| Otilia | Romanian, Spanish | Romanian and Spanish form of Odilia |
| Ouida | History | The pen name of the English author Ouida (1839 to 1908), from her childhood pronunciation of her middle name Louise |
If you like the feel of an older name, Opal and Olive from the first table are the classic English picks, and Ottoline and Ouida bring a literary, early 20th century mood. Odilia gives you a whole family to choose from: Odile in French, Ottilie in German, Ottilia in Swedish, Otilia in Romanian and Spanish, and Otylia in Polish.
Baby on the way? Get ahead on sleep.
Our free two-minute quiz builds a gentle, personalized sleep plan you can use from the first weeks at home.
Nature O Names: Oak, Ocean, Orchids and Violets
Nature names that start with O lean toward trees, water and flowers. The oak names are the modern group here: Behind the Name lists Oaklyn, Oaklynn, Oaklee and Oakleigh as modern English variants of Oakley, a surname that means “oak clearing”. For more water names, see our ocean names list.
| Name | Origin | Meaning |
|---|---|---|
| Ocean | English (modern) | From the English word for a large body of water, from Greek Okeanos; listed as feminine and masculine |
| Océane | French | From French océan: “ocean” |
| Oaklyn | English (modern) | Variant of Oakley (“oak clearing” in Old English) with the name suffix lyn |
| Oaklynn | English (modern) | Variant of Oaklyn |
| Oaklee | English (modern) | Variant of Oakley |
| Oakleigh | English (modern) | Strictly feminine variant of Oakley |
| Orquídea | Spanish, Portuguese | “Orchid” in Spanish and Portuguese |
| Orvokki | Finnish | “Pansy, violet” in Finnish |
| Onerva | Finnish | “Aftergrass, hay grown after harvesting” (an archaic Finnish word) |
| Ofra | Hebrew | “Fawn” in Hebrew |
| Oliva | Ancient Roman, Spanish, Italian | Latin name meaning “olive”; the name of a 2nd-century saint from Brescia |
| Ortal | Hebrew | From Hebrew or, “light”, and tal, “dew” |
| October | English (rare) | From the tenth month, from Latin octo, “eight”, because it was the eighth month of the Roman year |
Orquídea (orchid) and Orvokki (pansy or violet) are both everyday flower words in their own languages, Spanish and Portuguese for the first, Finnish for the second. Onerva is a gentler farm image, the grass that grows back after harvest. Ornella, from the first table, also belongs here in spirit, since d’Annunzio built it from a Tuscan word for the flowering ash tree. And Opal, the October birthstone, makes a sweet pair with October itself.
Mythology, Literature and Biblical O Names
Greek and Roman myth give O a strong set of names, joined by a Welsh legend, two Norse and German epics, and three names from plays and an opera. Ophelia, Oriana and Odette from the first table fit here too: one from Hamlet, one from medieval legend and one from Swan Lake.
| Name | Origin | Meaning |
|---|---|---|
| Oenone | Greek mythology (Latinized) | From Greek oinos: “wine”; a mountain nymph married to Paris before he went after Helen |
| Omphale | Greek mythology | From Greek omphalos: “navel, center”; a legendary queen of Lydia |
| Ops | Roman mythology | “Power, strength, wealth, abundance” in Latin; the wife of Saturn and mother of Jupiter and Juno |
| Ourania | Greek mythology, Greek | From Greek ouranios: “heavenly”; the Muse of astronomy and astrology |
| Olwen | Welsh, Welsh mythology, Arthurian cycle | “White footprint”, from Welsh ol, “footprint, track”, and gwen, “white, blessed”; the maiden of the tale Culhwch and Olwen |
| Oddrún | Old Norse, Norse mythology | From Old Norse oddr, “point of a sword”, and rún, “secret lore, rune”; a woman in a poem of the Poetic Edda |
| Ortrun | German (rare), Germanic | From Old German ort, “point”, and runa, “secret lore, rune”; a character in the medieval German epic Kudrun |
| Olympias | Ancient Greek | Feminine form of Olympos; the mother of Alexander the Great, and a 4th-century saint |
| Olivette | Literature | Feminine form of Oliver; the title character of Edmond Audran’s French opera Les noces d’Olivette (1879) |
| Orinthia | Literature | Possibly related to Greek orino, “to excite, to agitate”; used by George Bernard Shaw in The Apple Cart (1929) |
| Olinda | Literature, Portuguese, Spanish (Latin American) | A princess of Norway in the medieval Spanish tale of Amadis of Gaul; perhaps related to Greek olynthe, “wild fig tree”; also a Brazilian city |
| Orpah | Biblical | “Back of the neck” in Hebrew; Naomi’s second daughter-in-law in the Book of Ruth (Old Testament) |
| Ophir | Biblical, Hebrew | From the Hebrew name Ofir, meaning unknown; a son of Joktan and a place name in the Old Testament; listed as masculine and feminine |
| Osnat | Hebrew | Modern Hebrew form of Asenath (“belonging to the goddess Neith” in Ancient Egyptian), Joseph’s wife in the Old Testament |
Biblical girl names that start with O are few. Orpah is the clearest example: she is Naomi’s other daughter-in-law in the Book of Ruth. Ophir is a son of Joktan in the Old Testament and a place name, and its Hebrew form Ofir is now also used for girls. Osnat is the modern Hebrew form of Asenath, the wife of Joseph. For a broader list, see our biblical girl names.
A name’s story can come with baggage. Ophelia is a tragic figure in Hamlet, and Behind the Name notes that the name has been used since the 19th century in spite of that association. Read the full story of any literary name before you commit, so that nothing surprises you later.
International O Names by Language
The origins below use the reference’s own usage labels. French gives you polished forms of the classics, Spanish adds names from Catholic devotion such as Olvido, and Irish, Welsh, Breton and Basque each bring names that are rarely heard in the United States.
| Name | Origin | Meaning |
|---|---|---|
| Octavie | French | French form of Octavia |
| Ophélie | French | French form of Ophelia |
| Oriane | French | French form of Oriana |
| Orianne | French | French form of Oriana |
| Olympe | French | French form of Olympias |
| Olvido | Spanish | “Oblivion, forgetting” in Spanish, from a title of the Virgin Mary, Our Lady of Oblivion, Triumph and Mercies |
| Olaya | Asturian, Spanish | Asturian form of Eulalia: “sweetly speaking” in Greek |
| Olalla | Galician, Spanish | Galician variant of Eulalia |
| Omaira | Spanish (Latin American) | Probably a feminine form of Omar; most common in Colombia and Venezuela |
| Odalys | Spanish (Latin American) | Variant of Odalis, possibly an elaboration of Odilia |
| Odete | Portuguese | Portuguese form of Odette |
| Órlaith | Irish, Old Irish | “Golden ruler”, from Old Irish ór, “gold”, and flaith, “ruler, sovereign, princess”; borne by a sister of the king Brian Boru |
| Orlagh | Irish | Anglicized form of Órlaith |
| Oonagh | Irish | Anglicized form of Úna |
| Onóra | Irish | Irish form of Honora, a variant of Honoria (feminine form of Honorius) |
| Odharnait | Irish (rare) | From odar, “dun-colored, grayish brown, tan”, plus a diminutive suffix; an early Irish saint |
| Orna | Irish | Anglicized form of Odharnait |
| Owena | Welsh | Feminine form of Owen, the Anglicized form of Owain (of uncertain origin, possibly from Latin Eugenius) |
| Oighrig | Scottish Gaelic | From the older Gaelic name Aithbhreac, from an intensive prefix and breac, “speckled”; Anglicized as Effie, Euphemia and Affrica |
| Oanez | Breton | From Breton oan, “lamb”, used as a Breton form of Agnes |
| Oihana | Basque | Feminine form of Oihan: “forest” in Basque |
| Oihane | Basque | Feminine form of Oihan |
| Osane | Basque | “Cure, remedy” in Basque; an equivalent of Remedios proposed by Sabino Arana in 1910 |
| Olaug | Norwegian | From Old Norse Ólaug: anu, “ancestor”, and laug, possibly “vowed, promised, bound in oath” |
| Oddny | Norwegian | Norwegian form of Oddný: “point of a sword” plus “new” in Old Norse |
| Oline | Norwegian, Danish | Feminine form of Ole, the Danish and Norwegian form of Olaf (“ancestor’s descendant”) |
Irish names follow their own spelling rules, so learn the sound before you fall for the look. Behind the Name gives Órlaith as /ˈoːɾˠ.lˠə/, which is close to the Anglicized forms Orla and Orlagh, and Oonagh is said like Oona. There are more in our Irish girl names guide.
From Eastern Europe, Turkey, the Arabic-speaking world, West Africa and Mongolia come names with clear, vivid meanings. Many Yoruba and Igbo names are short sentences, such as “God gives care” or “gift from God”.
| Name | Origin | Meaning |
|---|---|---|
| Oleksandra | Ukrainian | Ukrainian form of Alexandra, the feminine form of Alexander |
| Olesya | Ukrainian, Russian | Ukrainian diminutive of Oleksandra; also the title of an 1898 novel by Aleksandr Kuprin |
| Olha | Ukrainian | Ukrainian form of Olga |
| Odarka | Ukrainian | Ukrainian variant of Dariya, the Ukrainian form of Daria |
| Ognyana | Bulgarian | Feminine form of Ognyan, from Bulgarian ognen: “fiery” |
| Oliwia | Polish | Polish form of Olivia |
| Otylia | Polish | Polish form of Odilia |
| Öykü | Turkish | “Story” in Turkish |
| Özge | Turkish | “Other, different” in Turkish |
| Özlem | Turkish | “Yearning” in Turkish |
| Öznur | Turkish | From Turkish öz, “essence, kernel, self”, and nur, “light” (of Arabic origin) |
| Omaima | Arabic | Alternate transcription of Umayma: “little mother” in Arabic; an aunt of the Prophet Muhammad |
| Oumou | Western African | Form of Umm (“mother” in Arabic) used in parts of French-influenced West Africa |
| Omolara | Yoruba | “Child is family” |
| Olufunke | Yoruba | “God gives care” |
| Oluchi | Igbo | “Work of God” |
| Onyinye | Igbo | “Gift” |
| Onyinyechi | Igbo | “Gift from God” |
| Ogechi | Igbo | “God’s time” |
| Oyuunchimeg | Mongolian | “Wisdom ornament”, from oyuun, “wisdom, intellect”, and chimeg, “ornament” |
Print accents and special letters exactly as the name is spelled (Ophélie, Océane, Órlaith, Onóra, Orquídea, Öykü, Özlem). U.S. paperwork does not always carry accents or special characters, so decide ahead of time whether you are comfortable seeing the name without them. If a name comes from a culture outside your own family, learn how it is said and used before you commit.
Gender Neutral O Names
Behind the Name lists each of these as both feminine and masculine. The English ones are mostly word names and surnames, and many of the rest are Hebrew, Yoruba, Igbo, Turkish and Southern African names whose meanings work for any child. Ocean and Ophir, from the tables above, are also listed for both. See our gender neutral names guide for more.
| Name | Origin | Meaning |
|---|---|---|
| Ollie | English | Diminutive of Oliver, Olivia or Olive |
| Oakley | English | From an English surname from place names meaning “oak clearing” in Old English |
| Onyx | English | The gemstone, from Greek onyx: “claw, nail” |
| Ori | Hebrew | “My light” in Hebrew |
| Osher | Hebrew | “Happiness” in Hebrew |
| Ofri | Hebrew | “My fawn” in Hebrew |
| Ofir | Hebrew, Biblical Hebrew | Hebrew form of Ophir; in modern times also used as a feminine name |
| Oni | Yoruba | “Today” in Yoruba |
| Olamide | Yoruba | “My wealth has arrived” |
| Olayinka | Yoruba | “Wealth surrounds me” |
| Oluwaseun | Yoruba | “God, thank you” |
| Obi | Igbo | “Heart” in Igbo |
| Onyekachi | Igbo | “Who is greater than God?” |
| Otobong | Ibibio | “From God” |
| Okuhle | Zulu, Xhosa | “That which is beautiful, that which is good” |
| Omid | Persian | “Hope” in Persian |
| Özgür | Turkish | “Free” in Turkish |
| Ömür | Turkish, Azerbaijani | “Life”, from Arabic umr |
| Ofa | Tongan | “Love” in Tongan |
| Odalis | Spanish (Latin American) | Possibly an elaboration of Odilia; mostly feminine, but commonly masculine in the Dominican Republic |
Odalis is a good example of how usage shifts by place: Behind the Name says it is feminine in most countries but commonly masculine in the Dominican Republic. Its variant Odalys, in the international table, is listed as feminine only.
Why Parents Love Girl Names That Start With O: Sound, Spelling and Nicknames
A few plain reasons parents keep coming back to O names:
- An O at the start gives a name an open, rounded first sound.
- Olivia gives the letter the current No. 1 girl name in the U.S., while Olga, Odilia and Octavia carry centuries of history.
- O covers many languages, from Irish and Welsh to Hebrew, Finnish, Turkish, Yoruba and Igbo.
- Several long O names shorten neatly into a nickname.
The letter O changes sound more than most. People will often read the name before they hear it, so check the first sound. This table uses the pronunciation printed on each name’s Behind the Name entry (in the International Phonetic Alphabet), with a plain-words guide to the first sound.
| Name | Pronunciation (IPA) | First sound |
|---|---|---|
| Olivia | /oʊ.ˈlɪv.i.ə/ or /ə.ˈlɪv.i.ə/ (English) | Long O (as in go), or a soft uh |
| Opal | /ˈoʊ.pəl/ | Long O |
| Ophelia | /oʊ.ˈfil.i.ə/ (English) | Long O |
| Olive | /ˈɑl.ɪv/ (American English) | Short O, like AH |
| Octavia | /ɑk.ˈteɪ.vi.ə/ (American English) | Short O, like AH |
| Orla | /ˈɔɹ.lə/ (American English) | OR, as in for |
| Oona | /ˈuː.nə/ (English) | OO, as in moon |
| Ouida | /ˈwiː.də/ (English) | W, as in we |
| Oanez | /ˈwɑ̃n.es/ (Breton) | W, as in want |
| Oenone | /i.ˈnoʊ.ni/ (English) | EE, as in see |
| Oihana | /oi̯.ˈa.na/ (Basque) | OY, as in boy |
| Öykü | /œj.ˈcy/ (Turkish) | Rounded Ö, a sound English lacks |
A few patterns stand out. In American English, Olive and Octavia open with a short AH sound, while Olivia, Opal and Ophelia open with a long O. Oona and Oonagh start with OO. Ouida and the Breton name Oanez start with a W sound, and the Greek myth name Oenone starts with an EE sound in English, which surprises almost everyone. If relatives will see the name on a card before they hear it, tell them how it is said.
| Full name | Short or related forms |
|---|---|
| Olivia, Olive | Ollie (the entry lists Ollie as a diminutive of both) |
| Olga, Olha | Olya |
| Oleksandra | Olesya |
| Ottilie | Ottoline |
| Oda, Odilia | Odette (a French diminutive of either) |
| Oria | Orietta |
| Órlaith | Orla, Orlagh (Anglicized forms) |
| Odharnait | Orna (an Anglicized form) |
Sibling, Twin and Middle Name Ideas
These pairings are ideas, not rules. Sister or twin sets that share a letter work best when the names differ in length, ending or first sound:
- Olivia and Opal
- Olive and Ottilie
- Ophelia and Octavia
- Odette and Oriana
- Oona and Orla
- Órlaith and Oonagh
- Ora and Orli
- Océane and Ophélie
- Oihana and Osane
- Ourania and Olympia
If you want the names to match without rhyming, pair across the sounds: a long O with a short O (Opal and Olive), or an OO name with an OR name (Oona and Orla). Pairs from one language, such as Oihana and Osane in Basque or Órlaith and Oonagh in Irish, share a style without sharing a meaning. For a brother, look at our list of boy names that start with O.
For middle names, contrast helps. A short middle name balances a long first name, and a longer middle gives a short first name some weight. Olivia Ora, Ophelia Oona, Opal Odette and Ora Octavia keep the double O. If you would rather vary the initials, try a short O name in the middle: Ona, Orla and Opal all slip easily after a longer first name.
The Initials Check and Other Quick Tests
Before you settle on girl names that start with O, run each finalist through four quick tests:
- Initials: write out first, middle and last initials. O is a vowel, so O names spell words more easily than most. Check that your three letters do not spell something you would not choose, and swap the middle name if they do.
- Say it out loud: call the full name across a room. A first name that ends in an a sound (Olivia, Octavia, Oriana) can blur into a surname that starts with a vowel, so listen for the join.
- Spelling: several O names have look-alike spellings (Orli and Orly, Ora and Orah, Odalis and Odalys, Oaklyn and Oaklynn). Decide whether you mind spelling it out for years.
- Nicknames: check the table above. If you dislike the obvious short form, assume someone will use it anyway.
One more check is optional: how common the name is. Olivia is No. 1 for girls born in 2025, so she is likely to meet other Olivias along the way. Some parents like that and some do not. For any other name, the SSA’s Popularity of a Name search lets you look up a name by sex and range of years. The SSA counts each spelling separately, so Orli and Orly, or Oaklyn and Oaklynn, are ranked as different names.
If you are stuck between two finalists, try each one in the sentences you will say most: calling her to dinner, introducing her to a neighbor, spelling it for a receptionist. The name that still feels easy after a few days of that is usually the one.
Related Betteroo Guides
- Girl Names That Start With N
- Girl Names That Start With W
- Short Girl Names
- Old-Fashioned Girl Names
- Nicknames for Girls
- French Girl Names
The Bottom Line
The letter O offers a wide range of girl names: Olivia at the top of the U.S. charts, quiet classics like Olive, Opal and Odette, rare finds like Opaline, Ottoline and Ombeline, nature names like Océane and Orquídea, and names from French, Irish, Hebrew, Basque, Finnish, Turkish, Yoruba, Igbo and Mongolian. Shortlist three to five, check the meaning, test the initials and the sound, and say each one out loud for a week.
Then give yourself permission to stop looking. A name you have checked, said aloud and still like after a week is a good name.
Frequently Asked Questions
What are the most popular girl names that start with O?
Olivia leads by a wide margin. It ranked No. 1 for girls born in the United States in 2025, according to the Social Security Administration, and it is the only O name in the girls’ top 10. Other familiar O names include Olive, Ophelia, Octavia, Opal, Odette, Oriana, Oona and Orla.
What is a rare girl name that starts with O?
Rare O names include Opaline, Orinda, Odetta, Oralie, Ottoline, Oria, Orsina and Osanne, which Behind the Name marks as rare in their languages. Ombeline, Obdulia and Orabela are also uncommon in the United States. The Social Security Administration leaves names with fewer than 5 occurrences out of its lists, so the rarest never appear there.
What are pretty O names for girls with nice meanings?
Taste is personal, but meaning can help. Orli means light for me in Hebrew, Ourania means heavenly, Órlaith means golden ruler, Orabela means golden-beautiful in Esperanto, Onyinye means gift in Igbo, and Ofa means love in Tongan. Opal, Orquídea and Orvokki bring a gemstone, an orchid and a violet.
What are short girl names that start with O?
Short O names include Ora, Orah, Orli, Orly, Orit, Oda, Ona, Oana, Olya, Oili, Outi and Ola, plus Opal, Olga, Oona, Orla, Orna and Ofra. Several began as short forms: Oana is a Romanian short form of Ioana, Ola is a Polish short form of Aleksandra, and Olya is a diminutive of Olga.
Are there biblical girl names that start with O?
A few. Orpah is Naomi’s daughter-in-law in the Book of Ruth, and her name means back of the neck in Hebrew. Ophir is a son of Joktan and a place name in the Old Testament, and its Hebrew form Ofir is now used for girls too. Osnat is the modern Hebrew form of Asenath, the wife of Joseph.
Which O names work for both girls and boys?
Behind the Name lists Ollie, Oakley, Onyx, Ocean, Ori, Osher, Ofri, Ofir and Ophir as both feminine and masculine. So are the Yoruba names Oni, Olamide and Oluwaseun, the Igbo names Obi and Onyekachi, Omid from Persian, Özgür and Ömür from Turkish, and Ofa from Tongan.
Calmer days, better nights.
Betteroo builds a personalized sleep plan for your baby. Take the free two-minute quiz and have it ready before the newborn weeks.
Related Betteroo Guides
7 Sources
- Social Security Administration. Popular Baby Names (top 10 names of 2025).
https://www.ssa.gov/oact/babynames/index.html - Social Security Administration. Background Information for Popular Names.
https://www.ssa.gov/oact/babynames/background.html - Behind the Name. Browse Names: feminine names with the first letter O.
https://www.behindthename.com/names/gender/feminine/letter/o - Behind the Name. Meaning, origin and history of the name Olivia.
https://www.behindthename.com/name/olivia - Behind the Name. Meaning, origin and history of the name Ophelia.
https://www.behindthename.com/name/ophelia - Behind the Name. Meaning, origin and history of the name Odilia.
https://www.behindthename.com/name/odilia - Behind the Name. Meaning, origin and history of the name Órlaith.
https://www.behindthename.com/name/o10rlaith
