Boy Names That Start With O: 140 Ideas

Boy names that start with O run from classics like Oliver, Owen and Oscar to rare finds like Oswin, Osric and Otho, and this list of 140 gives a checked origin and meaning for every one.

O is a warm, open letter for naming a son. It holds one of the most popular boy names in the country (Oliver), sturdy classics like Otto and Otis, Old English names that are ready for a comeback, heroes of Greek, Norse and Irish legend, and names from languages around the world.

We grouped these boy names that start with O by style: familiar, unique, strong, short, long, nature, mythology, biblical, international and gender neutral. Then come name families and nicknames, sibling and middle name ideas, and a quick initials check.

Key Takeaways

Oliver is the number 3 name for U.S. boys born in 2025, according to the Social Security Administration.
Familiar O names for boys also include Owen, Oscar, Omar, Otto, Otis, Orion, Orlando and Odin.
Rare options include Oswin (“god” plus “friend”), Ogden (“oak valley”), Osric and Otho.
Several famous O names have uncertain meanings, including Oliver, Orion and Odysseus, and an honest list says so.
Luo names like Ochieng, Omondi, Odhiambo and Otieno describe the time of day a child was born.

Table of Contents

Boy Names That Start With O at a Glance

Quick Answer

Standout O names for boys: Oliver, Owen, Oscar, Omar, Otto, Otis, Orion and Odin (familiar); Ogden, Oswin, Osric, Orrin and Otho (rare); Oz, Onur, Orhan and Odd (strong); Om, Oli, Ole and Ozzie (short); Oren, Ofek, Otso and Oriol (nature); and Oakley, Ocean, Onyx and Ori (gender neutral).

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 only possible, we say so.

How to read the tables: the Origin column uses the reference’s own usage labels, so “English (rare)” or “English (modern)” is its wording, not ours. When a name is a form, variant or diminutive of another name, that is what the entry states, and we add the root name’s meaning only when we checked that root’s entry too. Each name appears in only one table, and there are 140 in all.

Start with the best known baby boy names that start with O. For ideas beyond one letter, browse our full list of baby boy names.

Name	Origin	Meaning
Oliver	English, German, Swedish, Norwegian, Danish, Finnish, Estonian, Catalan, Serbian, Croatian, Macedonian, Slovene, Czech, Slovak, Carolingian Cycle	From Old French Olivier, possibly from Latin oliva, “olive tree”; an underlying Germanic name such as Old Norse Áleifr (see Olaf) is another possibility
Owen	Welsh, English	Anglicized form of Owain (see the mythology table)
Oscar	English, Irish, Portuguese (Brazilian), Italian, Swedish, Norwegian, Danish, Dutch, French, Irish Mythology	Possibly “deer friend,” from Old Irish oss, “deer,” and carae, “friend”; it may instead come from the Old English name Osgar; in Irish legend, the son of the poet Oisín
Omar	Arabic, Bosnian, Kazakh, Malay, Bengali, English, Spanish, Italian	Alternate transcription of the Arabic name Umar: “flourishing, living long”
Otto	German, Swedish, Norwegian, Danish, Dutch, English, Finnish, Germanic	Later German form of Audo, a short form of names beginning with a Germanic element meaning “wealth, fortune”; the name of four kings of Germany
Otis	English	From an English surname derived from the medieval given name Ode, a cognate of Otto
Orion	Greek Mythology	Meaning uncertain: possibly related to Greek horion, “boundary, limit,” or to Akkadian Uru-anna, “light of the heavens”; a legendary hunter and a constellation
Orlando	Italian, Spanish, Portuguese, Carolingian Cycle	Italian form of Roland (from Old German “fame” plus “land”); a knight of Charlemagne in Italian epic poems
Odin	Norse Mythology, English (Modern)	Anglicized form of Old Norse Óðinn, from óðr, “frenzied, furious, inspired”; the chief god of Norse mythology
Oswald	English, German	Old English os, “god,” plus weald, “powerful, mighty”; Saint Oswald was a 7th century king of Northumbria
Octavio	Spanish	Spanish form of Octavius (see the long names table)
Obadiah	Biblical	“Servant of Yahweh” in Hebrew; one of the twelve minor prophets of the Old Testament
Omari	Swahili	Meaning uncertain, possibly a Swahili variant of Umar
Olaf	Norwegian, Danish, German, Dutch, Polish	From the Old Norse name Áleifr: “ancestor’s descendant”; the name of five kings of Norway
Orson	English	From a Norman nickname, a diminutive of Norman French ors, “bear,” from Latin ursus

Familiar and classic O boy names with origins and meanings.

Oliver leads this letter. In the Social Security Administration’s list for babies born in 2025, Oliver is the number 3 name for boys, behind only Liam and Noah. If you love the sound but want something less common, the Oliver family on this page is large: Olivier, Oliverio, Oli, Olly and Ollie all grow from it.

Be honest with yourself about Oliver’s origin, because many lists oversimplify it. Behind the Name says it comes from Old French Olivier, which was possibly derived from the Latin word for “olive tree,” and that there may also be a Germanic name underneath, such as the Old Norse name that became Olaf. So “olive tree” is a possible meaning, not a settled one.

Several other familiar O names are old and widely traveled. Otto goes back to a Germanic element meaning “wealth, fortune” and was the name of four German kings. Otis began as an English surname built on Ode, a medieval cousin of Otto. Owen is the Anglicized form of the Welsh name Owain, and Oscar is possibly “deer friend” in Old Irish. Omar is a transcription of the Arabic name Umar, which means “flourishing, living long.”

A few familiar names, including Oakley, Ollie and Odell, sit in the gender neutral table further down, because Behind the Name lists them for both boys and girls.

Unique, Rare and Strong Boy Names That Start With O

If you want unique boy names that start with O, look here. Several of these are Old English names that faded after the Middle Ages, and the reference marks a number of them as rare in English today, which is exactly why they stand out.

Name	Origin	Meaning
Ogden	English (rare)	From a surname taken from a place name: “oak valley” in Old English
Osborne	English	From a surname that was a variant of Osborn (Old English os, “god,” plus beorn, “warrior, man”)
Orrin	Irish	Anglicized form of Odhrán (see the nature table)
Oran	Irish	Anglicized form of Odhrán (see the nature table)
Oswin	English (rare)	Old English os, “god,” plus wine, “friend”; a 7th century king of Northumbria
Osric	Anglo-Saxon	Old English os, “god,” plus ric, “ruler, king”; a courtier in Shakespeare’s Hamlet
Osmond	English (rare)	Old English os, “god,” plus mund, “protection”
Osbert	English (rare)	Old English os, “god,” plus beorht, “bright”
Ormond	English (rare)	From an Irish surname, an Anglicized form of Irish Gaelic Ó Ruaidh, from the given name Ruadh
Orrell	English (rare)	From a surname taken from a place name: “ore hill” in Old English
Odo	Germanic	Variant of Otto, typically Frankish; a 9th century king of the West Franks
Otho	Ancient Roman	Roman cognomen of unknown meaning, probably of Etruscan origin; a short-lived 1st century Roman emperor

Unique and rare O names for boys.

Notice the pattern: Oswin, Osric, Osmond and Osbert all start with the Old English element os, “god.” Add wine and you get “friend,” add ric and you get “ruler, king,” add mund and you get “protection,” and add beorht and you get “bright.” Oswald, from the first table, and Osborne belong to the same family. If you like the idea of brothers with linked names, this is a ready-made set.

Orrin and Oran are both Anglicized forms of the Irish name Odhrán, so they share a meaning with the original, which you will find in the nature table. Ogden and Orrell come from English place names, “oak valley” and “ore hill.” For more ideas off the beaten path, see our unique boy names guide.

For strong or cool boy names that start with O, meaning is a good guide. Oz means “strength” in Hebrew, Onur means “honor” in Turkish, and Odd, despite how it looks in English, comes from an Old Norse word for “the point of a sword.” Our strong boy names list has more in this style.

Name	Origin	Meaning
Oz	Hebrew	“Strength” in Hebrew
Onur	Turkish	“Honour” in Turkish (borrowed from French honneur)
Orhan	Turkish	Turkish or, of uncertain meaning (possibly “place”), plus han, “khan, ruler, leader”; a 14th century Ottoman sultan
Osman	Turkish, Kurdish, Albanian, Bosnian, Uyghur, Malay	Turkish form of Uthman, an Arabic name meaning “baby bustard” (a large bird); the founder of the Ottoman Empire
Oleg	Russian, Georgian	Russian form of the Old Norse name Helgi: “holy, blessed”
Odd	Norwegian	From Old Norse oddr: “point of a sword”
Ove	Swedish, Norwegian, Danish	Probably a modern form of Old Danish Aghi, a short form of names with Old Norse egg, “edge of a sword,” or agi, “awe, fear”
Oiva	Finnish	“Splendid” in Finnish

Strong and cool O names for boys.

A note on Odd and Ove: both are everyday names in Scandinavia, but in the United States Odd will read as an English word to most people. If you love it, consider it as a middle name, where it can honor a Norwegian relative without much teasing risk.

Short O Names for Boys (2 to 5 Letters)

Short O names are quick to write, easy for a toddler to say, and they pair well with a long surname. Many of them are the everyday nicknames of Oliver, Olaf and Oswald in different languages.

Name	Origin	Meaning
Om	Hindi, Marathi	From Sanskrit om, considered a sacred syllable because it represents the range of sounds the human voice can make
Oli	English, German	Short form of Oliver
Olly	English	Diminutive of Oliver
Olli	Finnish	Finnish variant of Olavi, based on Swedish Olle
Olle	Swedish	Swedish diminutive of Olaf or Oliver
Ole	Danish, Norwegian	Danish and Norwegian form of Olaf
Ola	Norwegian, Swedish	Norwegian and Swedish short form of Olaf
Ode	Medieval English	Medieval English form of Odo
Ott	Estonian	Possibly an Estonian form of Otto; it may also be inspired by an archaic Estonian word meaning “bear”
Oto	Czech, Slovak	Czech and Slovak form of Otto
Olu	Yoruba	Short form of Yoruba names beginning with olú or olúwa: “lord, God”
Ozzie	English	Diminutive of Oswald, Osborn and other names beginning with a similar sound
Ozzy	English	Variant of Ozzie

Short boy names starting with O.

Om is the shortest name on the page and one of the most meaningful. Behind the Name says it comes from the Sanskrit om, considered a sacred syllable because it represents the range of sounds the human voice can make. If the name comes from a faith tradition outside your family, take time to learn how it is used before you choose it.

More short O names are filed under other headings: Oz, Or, Ori, Obi, Odo, Odd, Ove, Otso and Orso are all three or four letters, and Otto, Otis, Oren, Ofek and Omar are not much longer. Our short boy names guide has more ideas across the alphabet.

Long, Elegant and Vintage O Names

Longer O names give your son a formal name for later in life and, often, a ready nickname for the toddler years. Oswald, Osvaldo and Oswaldo all point to Ozzie, and Oliverio leads naturally to Oli or Olly.

Name	Origin	Meaning
Octavius	Ancient Roman	Roman family name from Latin octavus: “eighth”; the original family name of the emperor Augustus
Octavian	History, Romanian	From the Roman name Octavianus, derived from Octavius; the name Augustus took after his adoption by Julius Caesar
Octave	French	French form of Octavius
Ottavio	Italian	Italian form of Octavius
Oliverio	Spanish	Spanish form of Oliver
Osvaldo	Spanish, Italian, Portuguese	Spanish, Italian and Portuguese form of Oswald
Oswaldo	Portuguese, Spanish	Variant of Osvaldo
Orazio	Italian	Italian form of Horatius, a Roman family name possibly from Latin hora, “hour, time, season,” though it may be of Etruscan origin
Onofrio	Italian	Italian form of Onuphrius, from Egyptian wnn-nfr: “he who is good, he who is happy”
Ottokar	German (rare)	German form of Odoacer, from Gothic “wealth” plus “vigilant”
Odilon	French	French form of Odilo, the masculine form of Odilia; Saint Odilo was an 11th century abbot of Cluny
Olegario	Spanish	From Olegarius, the Latinized form of a Germanic name, possibly Aldegar or Odalgar; a 12th century bishop of Barcelona
Orville	English	Invented by the 18th century writer Fanny Burney, who perhaps intended it to mean “golden city” in French; Orville Wright co-invented the first successful airplane
Orval	English	Variant of Orville

Long, elegant and vintage O boy names.

The Octavius group comes from the Latin word for “eighth.” It was the original family name of the emperor Augustus, and Octavian is the form he used after Julius Caesar adopted him. Octave, Ottavio and Octavio (from the first table) are the French, Italian and Spanish forms.

Orville has an unusual history. Behind the Name says it was invented by the 18th century writer Fanny Burney, who perhaps meant it to mean “golden city” in French, so even its meaning is a guess. Its most famous bearer is Orville Wright, who with his brother Wilbur invented the first successful airplane. Orval is a variant. Both have the vintage feel that many parents now love, along with Otis, Oswald and Ogden.

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.

Take the Free Sleep Quiz

Nature O Names: Trees, Animals, Sun and Sky

These names connect to the natural world through their stated meaning: a pine tree, the horizon, a bear, a color, and four Luo names that mark the time of day a child was born. The reference does not attach any symbolism beyond that, and neither do we.

Name	Origin	Meaning
Oren	Hebrew	“Pine tree” in Hebrew
Ofek	Hebrew	“Horizon” in Hebrew
Otso	Finnish	“Bear” in Finnish
Orso	Italian (rare)	Italian form of Ursus, a Roman cognomen meaning “bear”
Odhrán	Irish	From Old Irish Odrán, from odar, “dun-colored, grayish brown, tan,” plus a diminutive suffix; a saint who traveled with Saint Columba
Oriol	Catalan	From a Catalan surname meaning “golden”
Ochieng	Luo	“Born when the sun shines,” from Luo chieng, “sun”
Omondi	Luo	“Born early in the morning” in Luo
Odhiambo	Luo	“Born in the evening” in Luo
Otieno	Luo	“Born at night” in Luo

Nature inspired O names for boys.

The four Luo names are a lovely example of naming by circumstance. Ochieng means “born when the sun shines,” Omondi “born early in the morning,” Odhiambo “born in the evening” and Otieno “born at night.” These names come with a story built in. If your family is not Luo, learn more about the tradition before choosing one.

Bears turn up more than once on this letter. Otso is the Finnish word for “bear,” Orso is the Italian form of a Roman name meaning “bear,” and Orson, from the first table, comes from a Norman French word for a little bear. More nature links live elsewhere on the page: Oakley and Ogden contain the oak, Onyx is a gemstone and Ocean needs no explanation.

Mythology, Literature and Biblical O Names

Greek, Egyptian, Norse and Irish stories supply many O names, and so do medieval French romance and Shakespeare. Where the reference gives only a possible origin, as for Orpheus, Osiris, Owain and Othello, we say so. For Odysseus it calls the meaning unknown.

Name	Origin	Meaning
Odysseus	Greek Mythology	Meaning unknown, probably of non-Greek origin; traditionally linked to Greek odyssomai, “to hate”; the hero of the Odyssey
Orpheus	Greek Mythology	Perhaps related to Greek orphne, “the darkness of night”; the poet and musician who went to the underworld for Eurydice
Orestes	Greek Mythology	“Of the mountains,” from Greek oros, “mountain,” and histemi, “to stand”; the son of Agamemnon
Oceanus	Greek Mythology (Latinized)	Latinized form of Okeanos, the body of water the ancient Greeks thought surrounded the Earth, and the Titan who personified it
Ouranos	Greek Mythology	Greek form of Uranus, from ouranos: “the heavens”; the father of the Titans
Osiris	Egyptian Mythology (Hellenized)	Greek form of an Egyptian name of unknown meaning, possibly related to words for “mighty” or “eye”; the Egyptian god of fertility, agriculture and the dead
Óengus	Old Irish, Irish Mythology	Old Irish form of Aonghus, possibly “one strength”; an Irish god of love and youth
Oisín	Irish, Irish Mythology	“Little deer,” from Old Irish oss, “deer, stag,” plus a diminutive suffix; a warrior poet, the son of Fionn mac Cumhaill
Ossian	Literature	Variant of Oisín used by James Macpherson in his 18th century poems, where Ossian is the narrator
Owain	Welsh, Arthurian Cycle	From an Old Welsh name possibly from the Latin name Eugenius; other theories link it to Celtic roots for “sheep,” “good” or “desire” plus “born of”
Ogier	Carolingian Cycle	French form of Audagar (Old Frankish “wealth, fortune” plus “spear”); one of Charlemagne’s knights in medieval French romances
Oberon	Literature	Variant of Auberon; the king of the fairies in Shakespeare’s A Midsummer Night’s Dream (1595)
Othello	Literature	Perhaps a diminutive of Otho; the title character of Shakespeare’s tragedy (1603)
Orsino	Italian (rare)	Italian form of the Roman name Ursinus, from Ursus, “bear”; a duke in Shakespeare’s Twelfth Night
Ovid	History	From the Roman family name Ovidius, possibly from Latin ovis, “a sheep,” or of Sabellic origin; the 1st century BC Roman poet of the Metamorphoses

O names from mythology, legend and literature.

Some of these names belong together. Oisín is the warrior poet of Irish legend, and Oscar, in the first table, is his son. Ossian is the version of Oisín that James Macpherson used in his 18th century poems. Óengus is an Irish god of love and youth. In Greek myth, Orestes is the son of Agamemnon, Ouranos is the father of the Titans and Oceanus is the Titan of the great world river.

Shakespeare is a rich source here: Oberon is the fairy king of A Midsummer Night’s Dream, Orsino is a duke in Twelfth Night, Osric is a courtier in Hamlet, and Orlando, from the first table, appears in As You Like It. Orion is both a hunter of Greek myth and a constellation, so it fits our space names list too.

A gentle caution: myths are not always kind stories. Orestes and Othello both come from tragedies with violent plots. Plenty of parents use these names anyway, but it is worth reading the story before you commit.

For biblical boy names that start with O, Obadiah from the first table is the best known. Less common choices with Old and New Testament roots are below, and our biblical boy names list has many more.

Name	Origin	Meaning
Obed	Biblical, Biblical Latin, Biblical Greek	“Serving, worshipping” in Hebrew; the grandfather of David (Old Testament)
Omri	Biblical, Hebrew, Biblical Hebrew	Possibly “servant” in Hebrew (or a related Semitic language); a 9th century BC king of Israel
Othniel	Biblical	Meaning uncertain, possibly “lion of God” or “strength of God” in Hebrew; the first of the judges of the Israelites
Oded	Biblical, Biblical Hebrew	“To restore” in Hebrew; a prophet from Samaria (Old Testament)
Ohad	Biblical, Hebrew, Biblical Hebrew	Meaning uncertain, possibly related to Hebrew “to unite”; the third son of Simeon (Old Testament)
Ophir	Biblical, Hebrew	From a Hebrew name of unknown meaning; a son of Joktan, also a place name in the Old Testament
Ozias	Biblical Greek, Biblical Latin, Biblical French, Biblical	Form of Uzziah (“my power is Yahweh” in Hebrew) used in the Greek, Latin and French Bibles
Onesimus	Biblical, Biblical Latin	Latinized form of Greek Onesimos: “beneficial, profitable”; the man Paul sent back to Philemon (New Testament)
Olympas	Biblical, Biblical Greek, Biblical Latin, Ancient Greek	Probably a shortened form of a longer name such as Olympiodoros; mentioned briefly in the New Testament

Biblical O names for boys.

Several of these entries are honest about uncertainty. Othniel is possibly “lion of God” or “strength of God,” Omri possibly “servant,” and Ohad possibly related to a word for “to unite.” For Ophir the reference says the meaning is unknown. Ophir is also listed as both masculine and feminine, and its Hebrew form Ofir is in the gender neutral table.

International O Names by Language

The origin labels below are the reference’s own usage labels. Where an entry says only that a name is the form of another name in a given language, we print exactly that, and add the root’s meaning only where we checked the root entry.

Name	Origin	Meaning
Olivier	French, Dutch, Carolingian Cycle	French and Dutch form of Oliver; also a French word meaning “olive tree”
Oskar	German, Swedish, Norwegian, Danish, Estonian, Finnish, Polish, Czech, Slovene, Basque	Form of Oscar in several languages
Oskari	Finnish	Finnish form of Oscar
Olav	Norwegian, Danish	Variant of Olaf
Olof	Swedish	Swedish form of Olaf
Olavi	Finnish, Estonian	Finnish and Estonian form of Olaf
Onni	Finnish	“Happiness, luck” in Finnish
Øyvind	Norwegian	From Old Norse Eyvindr: ey, “island” or “good fortune,” plus vindr, possibly “victor”
Øystein	Norwegian	Norwegian form of Eysteinn: “island” or “good fortune” plus “stone”
Oreste	Italian	Italian form of Orestes
Orfeo	Italian, Spanish (rare)	Italian and Spanish form of Orpheus
Orestis	Greek	Modern Greek form of Orestes
Odysseas	Greek	Modern Greek form of Odysseus
Ondřej	Czech	Czech form of Andrew, from Greek andreios: “manly, masculine”
Oldřich	Czech	Czech form of Ulrich, from Old German “heritage” plus “ruler, king”
Oleksandr	Ukrainian	Ukrainian form of Alexander: “defending men”
Ostap	Ukrainian	Ukrainian form of Eustathius: “well-built, stable”
Osip	Russian	Russian form of Joseph: “he will add”

European O names for boys, grouped by language.

Scandinavia and Finland are especially generous with O names. Olaf alone gives you Olav, Olof, Olavi, Ole, Ola and Olle, and Finnish adds two word names with lovely meanings: Onni, “happiness, luck,” and Oiva, “splendid.” Eastern European forms are often surprising to English speakers: Ondřej is Andrew in Czech, Oleksandr is Alexander in Ukrainian and Osip is Joseph in Russian.

Name	Origin	Meaning
Ömer	Turkish, Uyghur	Turkish and Uyghur form of Umar: “flourishing, living long”
Ozan	Turkish	“Bard, poet” in Turkish
Osamu	Japanese	From Japanese osamu, “discipline, study,” as well as other kanji with the same pronunciation
Obinna	Igbo	“Heart of the father” in Igbo
Okechukwu	Igbo	“Portion of God” in Igbo
Olufemi	Yoruba	“God loves me” in Yoruba
Ousmane	Western African	Form of Uthman (“baby bustard”) used in parts of French-influenced West Africa
Oumar	Western African, Central African	Form of Umar used in parts of French-influenced West and Central Africa
Orel	Hebrew	“Light of God” in Hebrew

Turkish, Japanese, West African and Hebrew O names.

Igbo and Yoruba names often carry a full sentence of meaning: Obinna is “heart of the father,” Okechukwu “portion of God” and Olufemi “God loves me.” Several Yoruba names that start with O are listed for both boys and girls and appear in the next table. If a name comes from a culture or faith outside your own family, take time to learn how it is used and said before you choose it.

Print accents and special letters exactly as the name is spelled: Ömer, Øyvind, Øystein, Ondřej, Oldřich, Odhrán, Óengus and Oisín. U.S. paperwork does not always carry accents or special characters, so decide ahead of time whether you are comfortable seeing the name without its mark on some documents.

Gender Neutral O Names

Behind the Name lists each of these names as both masculine and feminine. Several are English word names or surnames, and others come from Hebrew, Persian, Igbo, Yoruba, Tswana and Sotho. More ideas: our gender neutral names guide.

Name	Origin	Meaning
Oakley	English	From an English surname taken from place names meaning “oak clearing” in Old English
Ocean	English (modern)	From the English word ocean, ultimately from Greek Okeanos
Onyx	English	From the English word for the gemstone, from Greek onyx: “claw, nail”
Ollie	English	Diminutive of Oliver, Olivia or Olive
Odell	English	From an English surname taken from a place name: Old English “woad” (a plant that makes a blue dye) plus “hill”
Ori	Hebrew	“My light” in Hebrew
Or	Hebrew	“Light” in Hebrew
Ofir	Hebrew, Biblical Hebrew	Hebrew form of Ophir; in modern times also used as a feminine name
Omid	Persian	“Hope” in Persian
Obi	Igbo	“Heart” in Igbo
Oluwaseun	Yoruba	“God, thank you” in Yoruba
Olamide	Yoruba	“My wealth has arrived” in Yoruba
Olayinka	Yoruba	“Wealth surrounds me” in Yoruba
Opeyemi	Yoruba	“Gratitude is suitable for me” in Yoruba
Ofentse	Tswana	“He or she has conquered” in Tswana
Omphile	Tswana, Sotho	“He has given” in Tswana and Sotho
Omega	Various	From the last letter of the Greek alphabet, often seen as a symbol of completion

Gender neutral names that start with O.

Light is a theme here: Or means “light” and Ori “my light” in Hebrew, and Orel, in the previous table, means “light of God.” If you are naming a daughter or want to compare lists, our same-day guide to girl names that start with O uses the same checked format.

Why O Names Are Loved, Plus Nicknames

A few plain reasons parents keep coming back to this letter:

O is an open, round vowel sound, so O names tend to feel warm and easy to say.
The range is wide: two letters (Om, Oz, Or) to four syllables (Octavius, Olegario, Onesimus), ancient (Ovid, Otho) to modern (Ocean, Onyx).
The meanings are appealing: “strength” (Oz), “hope” (Omid), “light” (Or), “happiness, luck” (Onni) and “heart” (Obi).
Vowel-first names flow nicely after many surnames and middle names, though you will want to say the full name out loud (see the checks below).

The big O names also travel well. Each line below groups names that the reference links to one another:

The Oliver family: Oliver, Olivier, Oliverio, Oli, Olly, Ollie and Olle.
The Olaf family: Olaf, Olav, Olof, Olavi, Ole, Ola, Olle and Olli.
The Oscar family: Oscar, Oskar and Oskari.
The Octavius family: Octavius, Octavian, Octave, Octavio and Ottavio.
The Otto family: Otto, Odo, Ode, Oto, Otis and possibly Ott.
The Oswald family: Oswald, Osvaldo, Oswaldo, Ozzie and Ozzy.
The Umar family: Omar, Ömer, Oumar and Omari (the reference calls Omari possibly a variant).

If a relative carries one of these names, another member of the same family is a quiet way to honor them without repeating the name exactly.

Full name	Nickname ideas
Oliver	Oli, Olly, Ollie, Olle (Swedish)
Oswald	Ozzie, Ozzy
Olaf	Ole (Danish, Norwegian), Ola (Norwegian, Swedish), Olle (Swedish)
Olavi	Olli (Finnish)
Osborne	Ozzie (the reference lists it as a diminutive of Osborn, and Osborne is a variant of Osborn)

Nickname ideas for O names, each linked on Behind the Name.

Sibling, Twin and Middle Name Ideas

These pairings are ideas, not rules. Brother or twin sets that share a letter work best when the names differ in length, ending or rhythm, so the two are not confused when you call up the stairs.

Oliver and Otto
Owen and Oscar
Otis and Orson
Oswin and Osric (both built on Old English os, “god”)
Orion and Odin
Oisín and Oscar (father and son in Irish legend)
Ochieng and Omondi
Oren and Ofek
Olav and Onni
Octavio and Orlando

You can also link brothers through meaning instead of sound. Oz and Othniel both carry strength. Or and Orel both carry light. Otso, Orso and Orson all lead back to a bear.

For a sister, the unisex picks Oakley, Ocean, Ori and Ollie keep the letter.

For middle names, contrast helps. A short first name can carry a longer middle, a long first name is balanced by a short one, and a middle that starts with a consonant keeps an O first name from running into it. Ideas: Otto James, Owen Theodore, Oscar William, Orion Henry and Octavius Lee. O names also make easy middle names themselves: Owen, Otis, Oscar and Orson sit comfortably in the second slot. Our middle names for boys list has more.

The Initials Check and Other Quick Tests

Before you settle on boy 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 initials can spell short words more easily than you expect. If a combination spells something you would rather not see on a backpack, swap the middle name.
Say it out loud: call the full name across a room. A first name that ends in a vowel sound (Otto, Orlando) can blur into a middle or last name that starts with a vowel, and two O sounds in a row can be a mouthful.
Spelling and sound: decide whether you mind correcting people. Oscar and Oskar, Ophir and Ofir, Osvaldo and Oswaldo, and Ozzie and Ozzy sound alike, and Irish names like Odhrán and Oisín are often misread by people who have not heard them.
Nicknames: check the table above. If you dislike the obvious short form, such as Ollie for Oliver or Ozzie for Oswald, assume someone will use it anyway.

If rarity matters to you, use the Popularity of a Name search on the Social Security Administration (SSA) baby names site. The SSA counts each spelling separately, so Oscar and Oskar have separate counts, and it leaves out names with fewer than 5 occurrences to protect privacy, so the very rarest names will not appear at all.

Related Betteroo Guides

The Bottom Line

The letter O covers nearly every style: a chart-topper in Oliver, sturdy classics like Owen, Oscar, Otto and Otis, rare Old English finds like Oswin, Osric and Osbert, heroes from Greek, Norse and Irish legend, and names from Hebrew, Turkish, Finnish, Igbo, Yoruba, Luo and more. Shortlist three to five, check the meaning, test the initials and say each one out loud for a week.

Once the name is settled, sleep is usually the next big project. Our newborn sleep schedule week by week is a gentle place to start.

Frequently Asked Questions

What are the most popular boy names that start with O?

Oliver is the clear leader: it is the number 3 name for boys born in 2025 in the Social Security Administration list, behind Liam and Noah. Other familiar O names include Owen, Oscar, Omar, Otto, Otis, Orion, Orlando and Odin. You can check how common any name is with the SSA Popularity of a Name search.

What are unique boy names that start with O?

Uncommon O names include Ogden, Oswin, Osric, Osmond, Osbert, Orrell, Ormond and Otho. Behind the Name marks several of them as rare in English. Oswin means god plus friend in Old English, Ogden comes from a place name meaning oak valley, and Otho was the name of a short-lived Roman emperor.

What is a strong boy name that starts with O?

Meaning can guide you. Oz means strength in Hebrew, Onur means honor in Turkish, Odd comes from an Old Norse word for the point of a sword, and Oiva means splendid in Finnish. Othniel possibly means lion of God or strength of God in Hebrew, and Orhan includes a word for khan or ruler.

What are biblical boy names that start with O?

Obadiah, one of the twelve minor prophets, is the best known. Others include Obed, the grandfather of David, Omri, a king of Israel, Othniel, the first of the judges, Oded, Ohad and Ophir from the Old Testament, and Onesimus and Olympas from the New Testament. Ozias is a form of Uzziah used in some Bibles.

What are short O names for boys?

Two letter O names include Om, Oz and Or. Three letter choices include Oli, Ole, Ola, Ode, Ott, Oto, Olu, Ori, Obi, Odo, Odd and Ove. Four letter options include Otto, Otis, Oren, Ofek, Omar, Olly, Olaf, Olav, Olof, Onni and Oiva. Many began as short forms of Oliver, Olaf or Otto.

Which O names work for both boys and girls?

Behind the Name lists Oakley, Ocean, Onyx, Ollie, Odell, Ori, Or, Ofir, Omid, Obi and Omega as both masculine and feminine. Yoruba names Oluwaseun, Olamide, Olayinka and Opeyemi are also used for both, as are Ofentse from Tswana and Omphile from Tswana and Sotho. Ophir, the biblical form of Ofir, is listed for both too.

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.