Theo vs Theresa
American parents have registered 405,831 Theresas since 1880, against 39,333 Theos. But in 2025 it was Theo that was commoner, 3,966 babies to 136.
Babies given each name, 1880–2025
Theo Theresa
Each line is every baby given the name that year, girls and boys added together — the only count that means the same thing for both names. A line breaks where the name fell below five babies in a year — the point at which the SSA stops publishing it — rather than being drawn through a figure nobody published. A single published year in a gap shows as a dot.
Who was ahead
Of the 146 years in which either name was published, Theresa for 131 years and Theo for 15 years. The lead changed hands once.
Side by side
| Theo | Theresa | |
|---|---|---|
| Total US births | 39,333 | 405,831 |
| Most in one year | 4,182 | 11,991 |
| Babies in 2025 | 3,966 | 136 |
| Estimated living today | 33,000 | 266,000 |
| Median age today | 4 | 62 |
| Peak year | 2023 | 1961 |
| Best rank | 78th boys | 35th girls |
| Rank in 2025 | 82nd | 1,548th |
| First recorded | 1880 | 1880 |
| Girls / boys | 3,503 / 35,830 | 404,613 / 1,218 |
A rank is a position within one sex’s list for one year, so the two rank rows are not subtracted from one another and the winning column is not marked on them. The living figure is a life-table estimate, not a count.
Which name is older
Half of the Theresas alive today are over 62; half the Theos are over 4. That is 58 years between them: two names in use at the same time, worn by two different generations.
Where each one is strongest
- Theo Utah (2.4×), Nevada (2.0×), Washington (1.8×)
- Theresa Vermont (2.2×), Maine (2.0×), Rhode Island (1.9×)
How much commoner the name is in that state than it is nationally, from births recorded since 1910.
Both names abroad
Countries whose statistics office publishes both names, so the comparison can be made somewhere other than the United States.
| Country | Theo | Theresa |
|---|---|---|
| France | 133,745 Théo | 2,285 |
| England and Wales | 43,001 | 664 |
| Austria | 3,481 | 10,779 |
| Belgium | 9,272 Théo | 20 |
| Switzerland | 4,225 Théo | 119 |
| Ireland | 2,114 | 1,965 |
| Norway | 3,754 | 238 |
| Scotland | 2,803 | 504 |
| Northern Ireland | 1,309 | 8 |
| Poland | 433 | 2 |
Every spelling a country files separately is added together, over whatever years that country publishes — which is not the same range in any two of them, so read the columns against each other and not the rows.
Compare something else
Related comparisons
Social Security Administration birth records, 1880–2025, public domain. Full histories: Theo and Theresa.