Is Jo a male or female name?
Jo is used as both a female and male name. In counted records, it is associated with female usage in United States at 99% and male usage in Norway at 100%. Country context changes the answer.
Result without a country hint
This is the response used when the request does not supply a country. It is a fallback, not a claim that every country has the same distribution.
- Association
- female
- Probability
- 98%
- Sample size
- 184,305
- Confidence
- high
Jo by country
Only sources that publish observation counts appear in this table. The probability is the dominant-gender share within that country source; sample sizes from different countries cover different years and should not be treated as population rankings.
| Country | Association | Probability | Sample | Source |
|---|---|---|---|---|
| United States US | female | 99% | 180,870 | ssa |
| Norway NO | male | 100% | 2,375 | ssb |
| England and Wales GB | female | 83% | 428 | ons |
| France FR | male | 66% | 310 | insee |
| Switzerland CH | male | 57% | 135 | bfs |
| Canada CA | female | 100% | 85 | statcan |
| Ireland IE | female | 100% | 73 | cso |
| Poland PL | female | 68% | 19 | pesel |
| Austria AT | male | 60% | 10 | statat |
Attested in 64 countries and territories
Presence means the name appears in a source for that country. Sources without counts cannot support a popularity share.
AG · AT · AU · BB · BD · BE · BI · BW · BZ · CA · CB · CH · CM · CY · DE · DM · ER · FJ · FR · GB · GD · GH · GY · IE · JM · JP · KE · KI · KN · LC · LR · LS · ME · MH · MT · MU · MW · NA · NG · NO · NR · NZ · PG · PH · PL · PW · RS · RW · SB · SC · SE · SL · SZ · TO · TT · TV · UG · US · VC · VU · WS · ZA · ZM · ZW
Jo over time
In the United States, 100% of the babies named Jo in the 1890s were girls, against 87.3% in the 2020s.
| Decade of birth | United States: girls | Babies |
|---|---|---|
| 1890s | 100% | 140 |
| 1900s | 100% | 311 |
| 1910s | 94% | 1,266 |
| 1920s | 98% | 7,061 |
| 1930s | 99% | 28,930 |
| 1940s | 99% | 48,719 |
| 1950s | 100% | 64,235 |
| 1960s | 99% | 20,402 |
| 1970s | 97% | 6,093 |
| 1980s | 93% | 2,139 |
| 1990s | 89% | 685 |
| 2000s | 74% | 302 |
| 2010s | 83% | 298 |
| 2020s | 87% | 220 |
Births per decade from the US Social Security Administration (1880–2024) and INSEE (France, 1900–2025); decades with fewer than 100 babies are left out. See boys' names that became girls' names and French names that changed sex.
Look up Jo with a country
Send a reliable two-letter country code when you have one. Preserve probability, sample size, confidence and source with the category.
curl "https://namegender.com/api/v1/gender?name=Jo&country=US" \
-H "Authorization: Bearer ng_live_xxxxxxxxxxxx"Copy failed. Select and copy the text.
Method and limits
Counted rows come from national registration sources that publish male and female totals. The attested-country list also includes sources that confirm presence but do not publish a sample size. Those two evidence types are kept separate.
Name data describes a population-level association. It does not identify an individual person's gender. Preserve unknown and low-confidence results, and do not use name inference for employment, medical, financial, insurance, legal or eligibility decisions.
Data version: 2026.10. Read the benchmark methodology and database provenance before applying a threshold.
Questions about Jo
Is Jo a male or female name?
Jo is used as both a female and male name. In counted records, it is associated with female usage in United States at 99% and male usage in Norway at 100%. Country context changes the answer.
Why can the result for Jo change by country?
A name can have different observed distributions in different populations. A country hint narrows the evidence used by the API instead of treating one global result as universal.
Does the name Jo identify a person's gender?
No. This page describes statistical associations in name records. It cannot identify an individual person and should not be used for consequential decisions.