1770+ Boy Names Ending in O

1770+ Boy Names Ending in O

Boy names ending in O offer many intriguing options, from such top names as Theo to unique O-ending names from Kylo to Zino.

Mateo is the most popular boy name ending with O right now, though there are nearly 100 O-ending boy names among the US Top 1000. Along with Mateo, other boy names in the US Top 1000 include Leo, Santiago, Diego, Romeo, and Antonio.

And there are hundreds more unique names for boys that end with the letter O worthy of your consideration. These range from the biblical Jethro to the ancient Greek Cosmo to the cool, modern Rio and Po.

Here are all Nameberry’s boy names that end with the letter O, ordered by their current popularity on Nameberry.

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  1. Arlo
    • Origin:

      Irish or English
    • Meaning:

      "between two hills"
    • Description:

      Quirky cool Arlo is now well and truly back. Last year it broke into the US Top 200 boy names and consistently ranks among the most popular boy names on Nameberry.
  2. Milo
    • Origin:

      Latin and Old German
    • Meaning:

      "soldier or merciful"
    • Description:

      Milo is most commonly considered to be Germanic name derived from the Latin word miles, meaning "soldier." However, there is evidence to suggest it also may have independently spawned from the Slavic root milu, meaning "merciful." Milo predates brother name Miles, a variation that evolved when the name immigrated to the British Isles in the Middle Ages. Mylo is an alternate spelling.
  3. Hugo
    • Origin:

      Latinized form of Hugh
    • Meaning:

      "mind, intellect"
    • Description:

      Hugo, the Latin form of Hugh, has more heft and energy than the original -- and of course we love names that end (or begin, for that matter) with an o. This one is especially appealing because it's backed up by lots of solid history and European style.
  4. Elio
    • Origin:

      Italian, Spanish
    • Meaning:

      "sun"
    • Description:

      Elio is a sunny and spirited Italian and Spanish name that makes a great crossover prospect, which could catch on as Enzo has. Elio is also currently popular in France, ranking in the Top 250.
  5. Leo
    • Origin:

      Latin
    • Meaning:

      "lion"
    • Description:

      Leo is a strong-yet-friendly name that was common among the Romans, used for thirteen popes, and is now at its highest point ever in the US thanks in part to Leonardo "Leo" DiCaprio.
  6. Otto
    • Origin:

      German
    • Meaning:

      "wealthy"
    • Description:

      Otto is cool again. Long a quintessential Old Man Name, Otto has been promoted to trending darling of adventurous baby namers.
  7. Theo
    • Origin:

      Diminutive of Theodore
    • Meaning:

      "gift of God"
    • Description:

      See the popularity graph below for the name Theo? It's been heading straight uphill since 2010, when it hopped back onto the Top 1000 after a 60+ year absence.
  8. Mateo
    • Origin:

      Spanish
    • Meaning:

      "gift of God"
    • Description:

      Mateo vaulted into the boys' Top 10 in 2023, ranking all the way up at Number 6. Counting Mateo and Teo along with Anglo equivalents Theodore and Theo make this by far the Number 1 boys' name in the US.
  9. Nico
    • Origin:

      Italian diminutive of Nicholas, Greek
    • Meaning:

      "people of victory"
    • Description:

      Nico is one of the great nickname names, full of charm, energy and effortless cool -- a neo Nick.
  10. Enzo
    • Origin:

      Italian variation of Henry, also diminutive of Vincenzo and Lorenzo
    • Description:

      Enzo originated as the Italian variation of Heinz, a German name derived from Heinrich, related to Henry. It has historically been used as a short form for Italian names such as Vincenzo and Lorenzo. The most famous bearer of the name is Enzo Ferrari, founder of the luxury sports car brand.
  11. Cosmo
    • Origin:

      Greek, Italian, English
    • Meaning:

      "order, beauty, universe"
    • Description:

      We all heard it on Seinfeld as the long-concealed first name of Kramer, then considered a punchline. Now some pioneering parents are embracing this expansive Greek name, which makes a creative and cool choice for a baby. Influential celebrity couple Scarlett Johansson and Colin Jost chose it for their son, born in 2021, which will likely drive Cosmo up in popularity. In the UK, it currently ranks within the Top 1000 boy names and is trending upwards.
  12. Apollo
    • Origin:

      Greek mythology name
    • Meaning:

      "destroyer"
    • Description:

      With mythological names rising, the handsome son of Zeus and god of medicine, music, and poetry among many other things might offer an interesting, if high-pressure, option.
  13. Inigo
    • Origin:

      Basque, medieval Spanish variation of Ignatius
    • Meaning:

      "fiery"
    • Description:

      Inigo, almost unknown in the U.S., is an intriguing choice, with its strong beat, creative and evocative sound, and associations with the great early British architect and stage designer Inigo Jones. The sixteenth-seventeenth century Jones shared his name with his father, a London clockmaker, who received it when Spanish names for boys were fashionable in England, especially among devout Roman Catholics.
  14. Ivo
    • Origin:

      German
    • Meaning:

      "yew wood, archer"
    • Description:

      Ivo is an unusual, catchy name with the energetic impact of all names ending in 'o'. Hardly heard in the U.S., it is used a bit more frequently in England, as is the related Ivor, a favorite of such novelists as Evelyn Waugh and P.G. Wodehouse. Ivo is currently most popular in the Netherlands.
  15. Emilio
    • Origin:

      Spanish and Italian variation of Emil
    • Meaning:

      "rival"
    • Description:

      Dashing and suave, with a hint of poetry and gentleness, Emilio is an appealing and international choice. A solid favorite in Italy, it is also on the rise in the US, France, Austria, and the UK.
  16. Jericho
    • Origin:

      Biblical place-name
    • Description:

      A biblical place name with trumpeting verve and strength.
  17. Zuko
    • Origin:

      Xhosa
    • Meaning:

      "glory"
    • Description:

      No, this name is not an homage to Grease! Zuko is a Xhosa (Zulu) boys' name meaning glory. In a world of Zekes, Zaks and Zanes, Zuko could make a refreshing choice for parents looking for something short and snappy.
  18. Cato
    • Origin:

      Latin
    • Meaning:

      "all-knowing"
    • Description:

      Cato conjures up images of ancient Roman statesmen and southern antebellum retainers; it could have revival potential, with its 'O' ending and the current interest in the names of Greek and Roman antiquity.
  19. Lorenzo
    • Origin:

      Italian variation of Laurence
    • Meaning:

      "from Laurentium"
    • Description:

      Latinizing Lawrence gives it a whole new lease on life. Like Leonardo, Lorenzo has been integrated into the American stockpot of names, partly via actor Lorenzo Lamas. Other associations are with Lorenzo de' Medici, the Florentine Renaissance merchant prince and art patron, Renaissance artists Ghiberti and Lotto, and the upstanding young man who married Shylock's daughter Jessica in Shakespeare's The Merchant of Venice.
  20. Viggo
    • Origin:

      Scandinavian
    • Meaning:

      "war"
    • Description:

      Though to most Americans Viggo is a one-person name attached to intense actor Mortensen, it is actually an old Norse name dating back to the Vikings, and is currently the 32nd most popular appellation in Sweden. Viggo Mortensen is a Jr., sharing his name with his Danish father.