Theo

Popularity, 1880–2025

girls named Theo boys named Theo

Girls and boys called Theo

years more girls than boys years more boys than girls

Theo crossed from girls to boys in 1926, and has stayed there for 19 of the years counted since. At its furthest it was 77% boys, and in 2025 it was 99%.

The girls’ share of each year’s babies of the name, in the 135 years in which at least 25 babies got it. The line touches the middle more often than there are crossings marked: a year or two on the other side is not a name changing hands, and only a move that holds for 5 counted years and reaches 60/40 is recorded as one. All 581 names that changed sex.

By the numbers

Total US births

39,333

Estimated living today

33,000

Median age today

4

Peak year

2023

Best rank

78th

Rank in 2025

82nd

First recorded

1880

Girls / boys

3,503 / 35,830

How old the living Theos are

born that year still alive today

Of the 39,333 babies given the name since 1880, about 33,000 are alive — 84 in every hundred. Roughly 29,000 of them are children and 1,000 are 65 or over. The dotted line is the median: half were born before 2021 and half after.

An estimate, not a count. SSA births aged forward through SSA cohort life tables, which know nothing about who left the country or arrived in it — so for a name that mostly came to America rather than being born in it, this is a floor rather than a figure. Where you fall among living Americans.

Where the name comes from

Origin Ancient Greek

Short form of Theodore, or of the rare given names Theobald, Theophilus or Theodoric, or of Theodora.

Etymology from Wiktionary, used under CC BY-SA 4.0.

Notable Theos

• Theo Walcott (born 1989)English association football player
• Theo van Doesburg (1883–1931)Dutch architect, painter, draughtsman and writer
• Theo van Gogh (1957–2004)Dutch film director
• Théo Hernandez (born 1997)French footballer
• Theo James (born 1984)British actor and musician
• Theo Van Gogh (1857–1891)Dutch art dealer (1857-1891), brother of painter Vincent van Gogh
• Theo Jörgensmann (1948–2025)German musician
• Theo de Raadt (born 1968)Leader of the OpenBSD project

People named Theo with articles in the most Wikipedia languages. Data from Wikidata (CC0).

Where Theo is most common

• CA3,960
• TX2,418
• NY2,280
• FL1,720
• IL1,341
• MA1,287
• PA1,256
• OH1,104
• MI997
• NJ930

Relative to how many babies each state records, Theo is most concentrated in Utah (2.4×), Nevada (2.0×), Washington (1.8×), Oregon (1.7×).

Total births recorded in each state since 1910. Browse names by state.

Names of 2023

The most popular boys’ names the year Theo peaked:

• Liam
• Noah
• Oliver
• James
• Elijah
• Mateo

All the names of 2023

Theo elsewhere

Counts come from each country's own records and are not comparable with the US figures above, which cover different years and a different definition of a recorded name. Where a country writes the name several ways, the spellings are added together and the most common is shown. A row marked name registrations is counting something else: Portugal ranks each of a child's two given names separately, so a girl registered Maria Leonor is in both the Maria row and the Leonor row, and that figure is not a number of children.

Theo: births by region

Parts of a country counted above, not extra births. The share is what makes the regions comparable: they differ in size by a factor of three hundred.

By canton, Theo is most concentrated in Jura, where 0.74% of children were given it – 108 of them.

Theo: rank by region

In 2025, Theo was given 5 times or more in 6 regions of Belgium.

In 2023, Theo was among the 10 most common names in 1 region of Italy.

In 2025, Theo was given 2 times or more in 13 regions of Poland.

In 2025, with the country taken in 11 areas rather than 3, Theo appears in the lists for Province of Walloon Brabant (Théo, 7th), Province of East Flanders (Theo, 13th), Province of Liège (Théo, 13th), Province of Hainaut (Théo, 15th), Province of Flemish Brabant (Theo, 16th), Province of West Flanders (Theo, 16th), Province of Namur (Théo, 18th), Province of Antwerp (Theo, 19th), Province of Luxembourg (Théo, 23rd), Brussels-Capital Region (Théo, 40th), Province of Limburg (Theo, 43rd), Province of Flemish Brabant (Théo, 57th), Province of West Flanders (Théo, 95th), Brussels-Capital Region (Theo, 114th), Province of East Flanders (Théo, 132nd) and Province of Antwerp (Théo, 341st).

Each of these is the top of a list the statistics office cut off somewhere – Belgium below 5 children, Italy after 10 names, Poland below 2 children – and published nothing after. So a region missing here is one where the name fell outside what was published, not one where it went unused. Places are shared where names tie, and the further down a list a place is, the more names can share it.

Theo by city

One city over a few years, so these are much smaller numbers than the national ones above and not comparable with them.

Theo among the living

How many people each country's register counts under the name, rather than how many were given it in any one year. Each register was read on one date, and they are not the same date.

A count of people on a register – the Netherlands on 1 January 2018, Finland on 4 August 2026 – and not of births, so it cannot be compared with the figures above. Names with very few bearers are withheld, and a dash in the first-forename column means the register would not say rather than that nobody goes by it.

Where Theo lives in Spain

Not a count of births but of people: 1,628 men called Theo were living in Spain on 1 January 2025, of every age, born in any year. Where they live is not spread evenly.

Men: the provinces where it is densest

Listed in 38 of Spain's 52 provinces. In the other 14 it is either held by fewer than 5 people – the point below which the source withholds a name – or it fell past the 5,000 names the source will print for one province. Neither means nobody there is called it. The rate is the source's own, not a share worked out here.

Related names

• Theresa
• Theodore
• Thelma
• Therese
• Thea
• Theron
• Theodora
• Theda
• Theadore
• Theophilus
• Theodis
• Theodor

Theo against another name

Two names on one chart, with the year one overtook the other.

• Theo vs Theresa
• Theo vs Theodore
• Theo vs Thelma
• Theo vs Therese
• Theo vs Thea
• Theo vs Theron

Compare Theo with a name of your own