Recorded 1880–2025 · United States
Theo was most popular in 2023, when 4,182 American babies were given the name — ranking #130 that year. In 2025 it ranked #144, with 3,966 births. Across 1880–2025 the Social Security Administration has recorded 39,333 people named Theo.
The Social Security Administration’s records begin in 1880, and Theo is already there in that first year — so the name is older than the record and these figures cannot date it. It has been recorded in 146 of the 146 years since.
The Social Security Administration has recorded 39,333 American births named Theo between 1880 and 2025. That is recorded US births, not a world population — it counts people issued a Social Security number at birth in the United States. Of those, roughly 33,234 are estimated to be alive today.
3,966 American babies were named Theo in 2025, ranking #144 that year.
Theo is rising. Across 2021–2025 it averaged 3,753 births a year, against 442 a year across 2011–2015 — a change of +748% over the decade.
Measured on recorded births. American births overall have fallen since 2007, so most established names lose births over any recent decade — a name can shed births and still hold its rank. Compare the rank above, which is measured against the other names of the same year.
Across the whole record Theo is mostly a boy’s name — 8.9% of the 39,333 Americans given it were girls and 91.1% were boys. It changed hands: since 1946 it has gone mainly to boys, having gone mainly to girls before that. In births since 2016 it is 1% girls and 99% boys.
Counted from every US birth the Social Security Administration recorded under this name, so it reflects use rather than opinion. A name given to fewer than five babies of one sex in a year is withheld at source and is not counted.
Roughly 33,234 Americans named Theo are alive today — 84% of everyone ever recorded with the name. The median is 5 years old, and half are between 3 and 9. That is a narrow band because Theo is a young name — it only became common recently, so almost everyone carrying it is still a child or a young adult.
An estimate, not a count. Recorded births are carried forward through the Social Security Administration’s 2023 period life table, by age and sex. That table describes mortality in one recent year, so it credits the oldest cohorts with today’s survival rather than the harsher rates they actually lived through — the further back a name peaked, the more this will overstate how many remain. It counts people issued a Social Security number at birth, not immigrants who arrived later.
How much more common the name is in each state than across the country as a whole.
See Theo on the interactive charts
About · Privacy · Contact
Source: U.S.A. Social Security Administration. Years 1880–2025. namelegacy.org