Given name & surname
Guillermo
“the determined protector”·“will”·“desire”
Guillermo is a variant of Guillaume. In French use, Guillaume carries the interpretation “the determined protector.” Guillermo is a form of William. William’s elements mean “will” or “desire” and “helmet” or “protection.” “Determined protector” is a natural interpretation of that combination.
Meaning & origin
What it means
Guillermo is a variant of Guillaume. In French use, Guillaume carries the interpretation “the determined protector.” Guillermo is a form of William. William’s elements mean “will” or “desire” and “helmet” or “protection.” “Determined protector” is a natural interpretation of that combination.
Explained through its name family
Where it comes from
Guillermo is a form of William. William is an English form of a Germanic name brought to England by the Normans.
Explained through its name family
How it developed
In Spanish use, Guillermo is used as a form of William. Guillermo is a form of William. The shared background comes through William: William joins the Germanic elements wil and helm. The second element began with the concrete image of a helmet and also carried the broader idea of protection.
Combines direct and name-family evidence
The story
Published U.S. birth records include this spelling as early as 1885. This is the earliest published observation available here, rather than a date for the name’s origin. Guillermo is a form of William. The history of William gives this family its wider story. William spread widely in England after the Norman Conquest, among people beyond the Norman ruling class. William remained prominent through the Middle Ages and became a royal name in England, Germany, and the Netherlands.
Combines direct and name-family evidence
Guillermo through the years
- Babies since 1880
- 32,148
- 32,074 boys · 74 girls
- Most popular year
- 1998
- 693 babies
- 2025
- 264
- #902 for boys
- 2021–25 vs 2016–20
- −5%
- Steady
Where it’s given
By the numbers
In 2025, this name appeared in 264 U.S. birth records for boys, ranking No. 902 among boys’ names. Average annual use for boys was 5.1% lower in 2021–2025 than in 2016–2020. Its largest published annual count for boys was 693 in 1998. In 2025, Texas had the largest reported state-level birth count for boys with this name (64). Published U.S. population figures for this spelling include 61,844 as a first name in 2020; 3,579 as a surname in 2020.
From Social Security birth records and U.S. Census name counts for this exact spelling. Other spellings are counted separately.
Guillermo’s family of names
In Spanish usage, Guillermo has a diminutive in GUILLE. In Spanish usage, Guillermo shares an earlier linguistic root with William. In Spanish usage, Guillermo has a conventional equivalent in the Irish form Liam.
Inner ring: spellings · middle: nicknames and forms · outer: across languages.
Around the world
Guillermo has relatives in 46 languages.
49 related names in 46 languages. Point at a dot, or tab to the map and use the arrow keys.
Nicknames & forms 7
Diminutives, pet forms, short forms and variants used alongside the name.
Spellings & scripts 1
The same name written differently, including transliterations into other scripts.
Across languages 46
Equivalents and cognates in other languages, plus older forms it grew from.
- LiamIrish
- Williamdoublet · Spanish, English
- Willequivalent
- WillemDutch
- WilhelmPolish, German
- Billequivalent
- Wiliamequivalent
- GuilhermePortuguese
Show 38 moreShow fewer
- Gillermoborrowing · Basque
- UilliamIrish
- GwilymWelsh
- VilhoFinnish
- ΓουλιέλμοςGreek
- GuilhermoPortuguese
- GuglielmoItalian
- VilémCzech
- ВільгельмUkrainian
- வில்லியம்Tamil
- VilhelmSwedish, Romanian
- ВильямRussian
- УильямRussian
- ВильгельмRussian
- GuilhèmOccitan
- WimDutch
- ВилијамMacedonian
- VilhelmasLithuanian
- ViljamsLatvian
- GulielmusLatin
- ウィリアムJapanese
- VilhjálmurIcelandic, Faroese
- VilmosHungarian
- ווילהלםHebrew
- GuillermeGalician
- GwillimWelsh
- VillemEstonian
- VilhelmoEsperanto
- ViljemSlovene
- ViliamSlovak
- VilimSerbo-Croatian
- 윌리엄Korean
- 威廉Chinese
- GuillemCatalan
- УилямBulgarian
- GwilhermBreton
- GuillénAragonese
- ويليامArabic
See also 3
Names our sources mention alongside this one. They are related in story or meaning, not forms of this name.
People named Guillermo
- Guillermo Lasso55th President of Ecuador from 2021 to 2023born 1955
- Guillermo del ToroMexican filmmaker and author (born 1964)
- Guillermo StábileArgentine football player and manager1905–1966
- Guillermo VilasArgentine tennis playerborn 1952
- Guillermo VarelaUruguayan association football playerborn 1993
- Guillermo CoriaArgentine tennis playerborn 1982
- Guillermo Cabrera InfanteCuban writer1929–2005
- Guillermo FrancoMexican footballerborn 1976
- Willy HernangómezSpanish basketball player (born 1994)
Listed by how widely each person is written about, which says nothing about the name itself.
Appears in
Similar names
If you love Guillermo, these share its style, era, origin or sound, from outside its own family.
Ronaldo
“the king's advisor”
>99% boys
Enrique
“the ruler of the estate”
>99% boys
Quinten
“from the queen's town or settlement”
>99% boys
Fernando
“a courageous voyager”
>99% boys
Rodrigo
“famous ruler”
>99% boys
Cesar
“an emperor; having a full head of hair”
>99% boys
Guillemette
“will” · “desire”
79% boys · 21% girls
Amer
“a prince” · “from the treetop”
>99% boys