Surnames starting with O

An Irish surname meaning “descendant of Boyle,” most strongly associated with Gaelic Ireland.

A famous Irish surname meaning “descendant of Brian,” ultimately tied to the personal name Brian.

An anglicized Irish surname meaning “descendant of Brian,” tied to the old Gaelic personal name Brian.

An Irish surname that likely began as a patronymic form of Bryant, ultimately tied to the personal name Brian.

A classic Irish surname meaning “descendant of Conall,” tied to an old Gaelic personal name that suggests strength or valor.

An Irish surname usually treated as a variant spelling of O'Connor, meaning a descendant of Connor.

An Irish surname meaning “descendant of Connor,” tied to one of the best-known Gaelic family names.

An Irish surname that may come from an old personal name or nickname, though some historical writers also linked it to Anglo-Saxon and Norse roots.

An Irish surname meaning “descendant of Domhnall,” a traditional Gaelic personal name usually understood as “world ruler.”

An Irish surname meaning “descendant of Gráda,” from a personal name associated with nobility or distinction.

An Irish surname meaning a descendant of a man named Halloran, from an older Gaelic personal name associated with strangeness or foreignness.

An Irish surname from the Gaelic O’Hara line, tied to an old noble sept recorded in medieval Ireland.

An Irish surname usually understood as a form of Ó hEathair or Ó hÁir, preserved in an Anglicized spelling with the prefix O'.

An Irish surname meaning a descendant of a name associated with the word for “gentle” or “kind.”

O'Leary is an Irish surname meaning “descendant of the clerk” or “descendant of the learned person,” from the Gaelic personal name derived from cleireach.

An Irish surname meaning “descendant of Laoghaire,” an old Gaelic personal name associated with a keeper of cattle or a plowman, depending on the interpretation.

An Irish surname meaning “descendant of the devotee of St. Malachy.”

An Irish surname from the Gaelic name Ó Meadhra, meaning a descendant of Meadhra.

A surname from the Irish O'Neill tradition, meaning a descendant of Neil or Niall.

An Irish surname meaning “descendant of Neil,” ultimately tied to the Gaelic personal name Niall.

An Irish surname meaning “descendant of Niall,” long associated with the great Gaelic ruling family of Ulster.

An Irish surname meaning “descendant of Quinn,” with the old prefix O’ marking paternal descent.

An Irish surname meaning “descendant of Reilly,” ultimately from a personal name associated with rallying or valour.

A classic Irish surname meaning “descendant of Ruarc,” a personal name associated with a famous medieval Gaelic dynasty.

An Irish surname from a powerful Gaelic sept once associated with territory between Galway and Clare.

An Anglicized Irish surname from a Gaelic personal name meaning “hawk-like” or “stately,” now best known through the O’Shea family name.

An Irish surname meaning “descendant of Súlbhán,” tied to one of the great Gaelic dynastic names of Munster.

An Irish surname from a Gaelic clan name meaning “descendant of Tadhg/Toole,” long associated with County Wicklow.

A surname for someone who lived by oak trees, oak woods, or a place called Oak/Oake.

A habitational surname meaning someone from an oak-wood or oak meadow.

A surname most likely referring to someone who lived by or among oak trees.

A surname that likely began as a medieval pet form of the old name Odo, Otto, or a related short Germanic name.

A surname found in Spanish-speaking regions, likely tied to place-based naming or an older local family name.

A surname with several possible roots, including a German topographic meaning “upper” or “higher,” though in some cases it may also reflect a shortened place-name or a different source altogether.

A German and Scandinavian surname meaning “upper mountain” or “from the upper hill.”

A Spanish surname most likely tied to a place-name, with roots in northern Spain.

A Spanish and Filipino surname originally written as a place name, meaning “from the field” or “from the countryside.”

A Spanish-language surname most likely from a given name, probably linked to the Latin name Occasion/Occasius or a related form.

A Spanish-language surname of likely regional origin, probably tied to a place name or local nickname rather than a clearly transparent everyday word.

A Basque surname that likely began as a patronymic from a personal name or nickname, later fixed as a family name.

A German surname originally referring to an ox, often from a house sign or a nickname for someone thought to resemble one.

An English locational surname from Odell in Bedfordshire, a place-name tied to the old barony of Wod(h)ull, meaning “wood hill.”

An old surname that may go back to the god Odin/Woden, or to an early personal name built from that element.

A surname of uncertain origin, probably a shortened or altered form of an older Germanic or English name.

An English surname most often treated as a place-based name, likely from a lost or reduced place-name, though its exact source is uncertain.

A surname with more than one possible origin, most likely from a place name or an old nickname-based form.

A place-based surname from English places named for oak trees or an oak grove.

A Scottish surname from the lands of Ogilvie in Angus, later associated with a prominent old Angus family.

An English surname tied to Northumberland, likely from a place-name and an older personal name behind it.

A habitational surname meaning “from Ogle’s farm or settlement,” with the final -by pointing to a Scandinavian place-name element.

A surname most likely from a place name or landmark, probably meaning someone who lived near or came from a notable oak tree.

A Korean surname most famously written Oh in English, usually representing the Korean family name 오.

A Spanish surname probably tied to a place name, likely referring to a holly or prickly thicket.

An English habitational surname meaning someone from Oldham in Lancashire, or from a similarly named old enclosure or landform.

A surname that usually began as a nickname for an older person, though it may also reflect shortened forms of older names like Auld.

A surname linked to the olive tree or olive groves, especially in Spanish-speaking regions.

A Scandinavian patronymic surname meaning “son of Ole.”

A Spanish surname most often linked to a place name or regional family name from the Hispanic world.

A surname with several possible roots, including a French given-name origin and, in some cases, a shortened form of Scandinavian or Gaelic names.

A likely German surname, probably built from a place-name or an older personal name rather than from an English word.

A surname originally linked to the word for “elephant,” likely first used as a nickname for a big or sturdy person.

A surname from the olive tree or olive fruit, used in several Romance-language traditions.

A Spanish surname meaning “olive groves” or “places with olive trees.”

A Spanish surname likely tied to the olive tree or an ancestor identified as "of Oliveira/Olivares."

A Spanish surname meaning “olives” or “olive trees,” likely referring to someone connected with olive growing or an olive grove.

A surname that usually comes from the personal name Olaf/Olive, though it was sometimes confused with Oliver and the word for the olive tree.

A Portuguese surname meaning “olive tree,” originally a name for someone living near olive trees or an olive grove.

A surname from the given name Oliver, probably strengthened in Britain by French and Scandinavian influence.

A surname tied to the olive tree, likely used for someone living near olive groves or from a place named for olives.

An Italian surname usually understood as a patronymic meaning “descendant of Oliver.”

A Spanish surname ultimately connected to the olive tree, likely arising as a patronymic or a regional form from the name Oliver.

A French surname most often connected with the olive tree, though some historians also link it to the old Scandinavian name Oliver.

A surname of Italian origin, usually from a personal name meaning “descendant of Oliver” or “olive-tree.”

A surname built from the olive tree or its fruit, likely used for someone connected with olive groves or the color of olives.

A Spanish surname originally referring to a place associated with elm trees.

A Spanish surname meaning “elm trees,” originally referring to a place marked by elms or a settlement near them.

A locational surname meaning someone from a place associated with elm trees or a green, wooded stead.

A locational surname for someone from Olney in Buckinghamshire, England.

A Scandinavian patronymic meaning “son of Ole” or “son of Olaf.”

A Scandinavian surname meaning “son of Ole,” with Ole itself a short form of Olaf or a related Nordic name.

A Polish surname meaning someone from a place with alder trees, or from a place called Olszewo/Olszewa.

A Spanish surname most likely tied to a place-name, especially the town of Olvera in Andalusia, Spain.

A name of Arabic origin, best known as a Muslim personal name rather than a traditional English surname.

A surname of Gaelic or Arabic appearance, most likely an Anglicized form of an older personal name or family name beginning with O' or Omar.

A surname with several possible roots, most likely a variant of Owen/Owney or a shortened form of a Gaelic given-name surname.

A rare surname with several possible roots, most likely tied to a place-name or an abbreviated older English/Continental form.

A Spanish surname likely tied to a place name, probably meaning someone from or associated with a location called Ontiveros.

A Basque surname probably taken from a place name, likely meaning something like a wooded or sheltered site.

A surname usually tied to the French town and principality of Orange, rather than the fruit.

An English surname of uncertain derivation, perhaps originally a place-name or a rare descriptive form later reshaped in spelling.

A likely Spanish surname from a place-name or regional name, most familiar today in Spain and the Spanish-speaking Americas.

A Spanish surname meaning “son of Ordoño,” ultimately from an old personal name of uncertain origin.

A Spanish surname most likely tied to a place-name, with some older writers linking it to a descriptive root connected to ears or the ear-shaped fruit of the wild hazel.

An Italian and literary surname from the heroic name Orlando, ultimately linked to the famous medieval Roland tradition.

A place-based surname meaning “Orm’s dwelling” or “Orm’s estate,” from a Scandinavian personal name plus an Old Norse/Old English place-name ending.

A Spanish and Portuguese surname most likely tied to a place-name, probably meaning someone from a locality called Ornelas.

A surname most likely of Spanish or Iberian origin, probably tied to a place name.

A Spanish surname, probably linked to a place-name and ultimately to words for “gold” and “weights/measures,” though the exact origin is not certain.

A Spanish surname most likely tied to a place name, especially a hill- or grove-related toponym.

A Basque surname from the valley or lordship of Orozco in Biscay, northern Spain.

A surname with two main roots: in Scotland and Ireland it likely means “pale” or “sallow,” while in England it may be locational.

A surname with likely Spanish or Catalan roots, probably tied to a place-name or, more broadly, to a word meaning “garden” or “planting.”

A Spanish surname most likely taken from the common plant ortiga, meaning “nettle,” or from a place named for it.

A likely Hispanic surname that is often a regional or altered form of Ortega or Ortiz-style names, rather than a distinct ancient root of its own.

A surname with several possible roots, including an old personal name and a place-name element meaning “guard.”

A very common Spanish surname that began as a patronymic, originally meaning “son of Orto” or “son of Fortún/Ortún” in medieval Iberia.

A habitational surname from several English places called Orton, usually meaning “upper farmstead” or similar.

An old baptismal surname from the Norse name Ásbjörn, meaning “god-bear.”

A classic English surname from the Old Norse given name Ásbjǫrn, meaning roughly “god-bear” or “divine bear.”

An old personal-name surname likely meaning “divine bear” or “god-bear,” preserved in a shortened medieval form.

A Hispanic surname most likely tied to a place name or local geographic feature in Spanish-speaking tradition.

A surname from an old Anglo-Saxon personal name, preserved in medieval records and place-names.

An English surname that can come from the old personal name Osmund, or less commonly from a Scandinavian byname meaning “east man.”

A Spanish surname traditionally linked either to an old noble family name or to a nickname built from the idea of daring or boldness.

A surname found in Spanish-speaking regions, probably from a nickname or byname linked to the Basque word for “vinegar.”

A surname that likely developed from a personal name, especially a Scandinavian/Manx form related to Old Norse naming traditions.

A surname usually meaning “east” or “eastern,” often used for someone from the east or living east of a place.

A surname most likely built from the German word for “eastern man,” or from a similar place-based name.

A Dutch surname likely referring to a man from the east shore or eastern bank.

A surname most likely of Scandinavian origin, probably built from a place-name or older personal-name element rather than an English occupational term.

A Polish surname meaning someone from a place called Ostrow/Ostrów, originally referring to an island, river island, or meadowy lowland.

A Spanish toponymic surname from the town of Osuna in Andalusia.

An old Germanic personal-name surname meaning “divine power” or “god’s rule.”

A patronymic surname meaning “son of Oswald,” developed as a shortened or altered form of an old Germanic personal name.

A Spanish habitational surname meaning someone from a hill, rise, or upland ridge.

A surname with several possible roots, most likely a medieval personal name or a nickname tied to hearing or status.

A surname with multiple possible roots, including a shortened form of old personal names like Otto, Odo, or Othar, and in some cases a variant spelling related to Oates or other names.

A short surname that usually comes from a medieval pet form of Otto or other names based on the old Germanic root for “wealth” or “fortune.”

A West Germanic patronymic surname meaning “son of Otto” or “belonging to Otto.”

A Germanic surname from an old personal name meaning “wealth” or “prosperity,” also later used as a short form of related names.

A Chinese surname most often written Ou in pinyin, with several possible historical characters and regional traditions behind it.

A French-Canadian surname, probably from a diminutive of a personal name, especially one related to Olivier or a similar old French given name.

A surname most likely from an old place-name or a personal name, with spellings shaped by medieval English sound changes.

A surname that likely began as a nickname or label for someone outside the law—literally an outlaw.

A Spanish surname most often linked to a place-name, especially the town of Oviedo or other regional toponyms in the Spanish-speaking world.

A surname of Scandinavian flavor, likely meaning someone from or near an upper farm or higher settlement.

Likely a habitational or descriptive surname built on Middle English over, with a later association to an “overman” as a foreman or supervisor.

A surname most likely formed from a place-name or street-side description, literally suggesting someone who lived by an upper or prominent street.

A common English place surname meaning “upper farm/settlement” or sometimes “bank or shore farm.”

A Spanish surname taken from the city of Oviedo in northern Spain.

A Welsh and Irish surname from a very old personal name, long associated with descent from a man called Owen or Eoghan.

A patronymic surname meaning “son of Owen,” especially common in Wales and among people of Welsh descent.

A surname most likely built from the personal name Owen, meaning “descendant of Owen.”

A surname of uncertain origin, most likely a regional or altered form built around an older personal or place-name base.

A habitational surname from the city of Oxford, originally meaning “the ford of the oxen.”

A habitational surname meaning “from the ox meadow” or “ox pasture,” originally tied to small local places in England.

Likely an occupational surname meaning an oilman or dealer in oil, though some early writers also linked it to Oliver.

A Spanish-language surname most likely tied to a place name or regional family line in the Iberian world.