Guillermo
Boy name · #902 in 2025 · Rare
How old is the name Guillermo? In official American birth records, Guillermo has been tracked continuously since 1885, giving it 140 years of documented American history.
Guillermo ranks #902 among American boys' names as of 2025, with 264 newborns given the name that year. A decade ago it stood at #661, so the name has been falling over the past ten years. Roughly one in every 6,818 boys born in 2025 was named Guillermo.
Babies named Guillermo per year. Source: Official national birth records.
The 140-year story
Guillermo first appears in the Social Security records in 1885, when 5 boys received the name. Its peak came in 1998, when 693 boys were named Guillermo — good for #369 that year. Today's parents encounter it on its way down the popularity curve, which for many parents is exactly the appeal. Following the curve matters more than today's snapshot: a name's position on its rise-peak-decline arc is the best predictor of how common it will feel in a kindergarten class five years from now.
Unlock the 5-year forecast and compare Guillermo against up to 5 other names.
Uniqueness: will there be another Guillermo in class?
On our rarity read — which blends how common Guillermo is today with its five-year momentum — the name reads as "rare". A high score means genuine rarity — your Guillermo will likely be the only one in the room, with the occasional spelling-out as the price.
Where Guillermo is most common
Geography matters for names, and Guillermo is no exception. Adjusted for how many boys are born in each state, Guillermo is most common in AZ (0.5 per 1,000), TX (0.4 per 1,000), CA (0.3 per 1,000), WA (0.3 per 1,000), FL (0.1 per 1,000) — against a national average of about 0.2 per 1,000 boys. These are per-capita rates, so they show where Guillermo is a genuine regional favorite rather than just where the most babies are born.
Names like Guillermo
Statistically, parents drawn to Guillermo tend to be choosing among names with similar popularity arcs, era profiles, and sounds — the closest matches in our model are Gerardo, Gustavo, Gonzalo, Gilberto, and Ernesto.
GerardoGustavoGonzaloGilbertoErnestoAlfredoBernardoAlberto
Rank history (last 25 years)
| Year | Babies named Guillermo | Rank |
|---|---|---|
| 2025 | 264 | #901 |
| 2024 | 299 | #831 |
| 2023 | 294 | #833 |
| 2022 | 287 | #848 |
| 2021 | 299 | #811 |
| 2020 | 275 | #832 |
| 2019 | 320 | #747 |
| 2018 | 314 | #751 |
| 2017 | 289 | #795 |
| 2016 | 322 | #754 |
| 2015 | 389 | #661 |
| 2014 | 376 | #676 |
| 2013 | 348 | #688 |
| 2012 | 392 | #619 |
| 2011 | 408 | #604 |
| 2010 | 457 | #553 |
| 2009 | 534 | #507 |
| 2008 | 583 | #476 |
| 2007 | 610 | #454 |
| 2006 | 621 | #439 |
| 2005 | 616 | #434 |
| 2004 | 639 | #406 |
| 2003 | 595 | #428 |
| 2002 | 626 | #404 |
| 2001 | 620 | #402 |
Frequently asked questions
How old is the name Guillermo?
In official American birth records, the name Guillermo first appeared in 1885 (over 140 years ago), when 5 newborn boys received the name. It has over a century of continuous American history.
Is Guillermo a popular boy name?
Guillermo ranked #902 among boys in 2025 with 264 babies given the name — outside the top 500, making it an uncommon pick. Ten years earlier it ranked #661.
When was the name Guillermo most popular?
Guillermo peaked in 1998, when 693 American boys received the name (ranked #369 that year). Since 1998 the name has declined from that high.
How rare is the name Guillermo?
In 2025, roughly 1 in 6,818 newborn American boys was named Guillermo. On our rarity scale (rarity blended with momentum) we classify it as "rare".
Data source: Official American birth records, 1880–2025, national and state files. Counts reflect registered birth records for American families.