Boys' name · peaked in 1996
Guillermo name popularity since 1925
31,488 babies born in the US from 1925 to 2025 were named Guillermo. Half of them were born in 1993 or earlier, so the typical Guillermo is about 33 years old in 2026. Guillermo peaked in 1996 as the #352 name for boys, and it ranked #902 in 2025.
Key facts
- US babies since 1925
- 31,488
- Named Guillermo, 1925–2025
- In 2025
- #902
- for boys in 2025 (264 babies)
- Girls / boys
- 99.8% boys
- 74 girls · 31,414 boys
- Most popular in
- Arizona
- 3.94× its national share
Peak year is the year Guillermo made up the largest share of US boys, in records going back to 1880. Typical age is based on births from 1925 on, not on who is living today.
Guillermo births per year, 1925–2025
The biggest year by count was 1998. Measured as a share of all babies, Guillermo peaked in 1996.
- Fastest rise: Between 1963 and 1968, Guillermo became 1.8× more common, from 1 in 10,500 baby boys to 1 in 5,950.
- Steepest fall: Between 2008 and 2013, its share of baby boys fell by 36%, from 1 in 3,500 to 1 in 5,440.
Shaded on the chart. Both compare Guillermo's share of all US boys five years apart, counting only years with at least 100 babies named Guillermo.
Decade by decade
Babies named Guillermo in each decade, and its rank among boys' names in the middle year of the decade (1935, 1945 … 2025).
| Decade | Girls | Boys | Rank |
|---|---|---|---|
| 1925–29 | 0 | 476 | – |
| 1930s | 0 | 783 | #720 |
| 1940s | 0 | 943 | #626 |
| 1950s | 0 | 1,495 | #604 |
| 1960s | 5 | 2,107 | #539 |
| 1970s | 5 | 3,357 | #416 |
| 1980s | 25 | 4,363 | #409 |
| 1990s | 34 | 6,462 | #380 |
| 2000s | 5 | 6,095 | #434 |
| 2010s | 0 | 3,615 | #661 |
| 2020–25 | 0 | 1,718 | #902 |
Ranks count every name given to at least 5 boys that year, so they can go past 1,000.
Generation fingerprint
29.7% of babies named Guillermo from 1925 to 2025 were born in the Gen Z years (1997–2012). The full split by generation:
Where Guillermo is most popular
The index compares Guillermo's share of babies in each state with its share nationwide, 1925–2025 (1.50× = 50% more common). States with at least 300 babies named Guillermo.
| State | Index | Babies |
|---|---|---|
| Arizona | 3.94× | 1,474 |
| Texas | 3.80× | 8,592 |
| California | 3.62× | 11,044 |
| New Mexico | 2.45× | 391 |
| Florida | 1.36× | 1,422 |
Names with a similar story
Of the other 1999 names on this site, these six had the share of babies closest in shape to Guillermo's from 1925 to 2025, however common each one got. Each line is scaled to its own high; the dashed line is Guillermo.
Names from the same era
Other common names that peaked within two years of Guillermo (1996).
Source: U.S. Social Security Administration national and state baby-name data, which covers names given to at least 5 babies of one sex in a year. About the data