Cassidy
Cassidy was the 541st most popular name for girls in 2025, given to 558 babies. Its best year was 1999, when it ranked 99th with 3,395 babies. Over the last ten years it has moved down 284 places. More babies were named Cassidy in the 2000s than in any other decade.
Meaning curly-haired (Irish Ó Caiside) · Irish
Say it KAS-ih-dee /ˈkæsɪdi/
- Rank in 2025
- #541 girls, down 130 places since 2020
- Babies in 2025
- 558girls
- Girls and boys
- 92% girls, 8% boys2021–2025
- Peak year
- 19993,395 babies
- Total since 1880
- 64,583babies recorded
What does the name Cassidy mean?
Cassidy is an Irish surname from Ó Caiside, "descendant of Caiside", a byname which Wiktionary derives from cas, "curly", so "curly-haired". Woulfe's 1923 index lists Cassidy and Cassedy among the English forms. As a first name it is used for boys and, since the 1980s in the US, mostly for girls.
Ó Caiside (Irish, “descendant of Caiside”)cas (Irish, “curly”)
How sure is this? Probable. The 'curly' reading is given by Wiktionary; it needs an Irish dictionary check.
Related names: Cassie, Cass, Kassidy.
See also: Irish names.
Sources for this meaning
- Wiktionary, entry 'Cassidy', Wiktionary (Wikimedia Foundation)
- Patrick Woulfe, Sloinnte Gaedheal is Gall: Irish Names and Surnames (1923), index of Irish surnames and their anglicized forms, M. H. Gill & Son (Internet Archive scan)
Nicknames for Cassidy
The usual nicknames for Cassidy are Cassie and Cass. Some parents skip the long form: for every 100 girls named Cassidy in the last five years, 29 were named Cassie, against 21 twenty years earlier.
| Nickname | Kind | Rank 2025 | Girls, 5 years |
|---|---|---|---|
| Cassie · also for Cassandra | Traditional | #1,280 | 925 |
| Cass · also for Cassius, Cassandra, Cassian | Traditional | — | — |
Nicknames reviewed by our editors; counts are girls given the nickname as their legal first name. Nobody records how many Cassidys go by each one.
Cassidy popularity since 1880
| Year | Rank (girls) | Rank (boys) | Babies (girls) | Babies (boys) |
|---|---|---|---|---|
| 2025 | #541 | #2,575 | 558 | 51 |
| 2020 | #411 | #2,735 | 765 | 45 |
| 2010 | #251 | #2,435 | 1,286 | 51 |
| 2000 | #107 | #2,302 | 3,163 | 42 |
| 1990 | #471 | #923 | 521 | 125 |
| 1980 | #1,077 | #1,135 | 131 | 64 |
| 1970 | #4,529 | #2,641 | 12 | 13 |
| 1960 | — | — | — | — |
| 1950 | — | — | — | — |
| 1940 | — | — | — | — |
| 1930 | — | — | — | — |
| 1920 | — | — | — | — |
| 1910 | — | — | — | — |
| 1900 | — | — | — | — |
| 1890 | — | — | — | — |
| 1880 | — | — | — | — |
How popular is Cassidy, counting every spelling?
Cassidy is the most common spelling of a name family that ranked #400 for girls in 2025 once every spelling is counted together, compared with #541 for Cassidy on its own. Together these spellings went to 824 girls in 2025.
| Spelling | Babies 2025 | Official rank | Babies 2021–2025 |
|---|---|---|---|
| Cassidy | 558 | #541 | 3,140 |
| Kassidy | 240 | #1,039 | 1,536 |
| Kassidi | 15 | #7,310 | 99 |
| Cassidee | 6 | #13,534 | 30 |
Spellings count together when they sound the same in American English and are used for the same sex; nicknames and forms that sound different (such as Theo and Theodore) are kept apart. How we group spellings.
How many kids will share the name Cassidy?
558 of the 3,606,400 babies born in the US in 2025 were named Cassidy (0.15 per 1,000 births). For a girl named Cassidy born in 2025, the chance that another child with the same name is in a class of 20 children the same age is under 1 in 50. If every grade liked the name as much as the 2025 babies do, only about one elementary school in 15 (of 430 pupils) would have a child named Cassidy.
Shares of all registered births (NCHS); classes assumed to be children born the same year. How we estimate this.
How old are people named Cassidy?
About 60,000 people born in the US named Cassidy are alive today, with a median age of 25; half are between 16 and 29. That makes Cassidy mostly worn by children and young adults.
Babies given the name each year (SSA) times the share of that birth year still alive (SSA life tables). Counts people born in the US only. Method.
Cassidy by state
How common Cassidy was among girls born in each state in 2021–2025. It is notably more common than nationally in Maryland (2.1×), Pennsylvania (2.0×), New Jersey (1.9×), Colorado (1.8×), Massachusetts (1.7×). It is least common, relative to the national rate, in West Virginia, New Mexico, Arkansas.
Names with a similar history
These names rose and fell in step with Cassidy: their share of US girls followed the most similar curve since 1880. If you like Cassidy, they share its era and feel.
Middle names for Cassidy · Sibling names for Cassidy
Questions about the name Cassidy
What does Cassidy mean?
Cassidy means “curly-haired (Irish Ó Caiside)” (Irish origin). Certainty: probable.
How popular is the name Cassidy?
Cassidy was the 541st most popular name for girls in 2025, given to 558 babies. Its best year was 1999, when it ranked 99th with 3,395 babies. Over the last ten years it has moved down 284 places. More babies were named Cassidy in the 2000s than in any other decade.
Is Cassidy a boy or girl name?
In 2021–2025, 92% girls, 8% boys given the name Cassidy in the US.
Where is Cassidy most popular?
In 2021–2025, Cassidy was most common in Maryland (0.82 per 1,000 girls), followed by Pennsylvania and New Jersey.