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The short answer
Declan is a masculine name of Irish origin, the anglicized form of Irish Deaglán and Old Irish Declán. Behind the Name says the name is of unknown meaning, though it likely begins with the Old Irish prefix dag meaning "good". It is pronounced DEK-lən. Its bearer Saint Declan was a 5th-century missionary to the Déisi peoples of Ireland and founded the monastery at Ardmore. Behind the Name also notes that in America the name received boosts in popularity from main characters in the films The Jackal (1997) and Leap Year (2010). In the United States it ranked #139 for boys in 2025.
Meaning and etymology
Behind the Name gives Declan as the "anglicized form of Irish Deaglán, Old Irish Declán, which is of unknown meaning, though it likely begins with the Old Irish prefix dag 'good'". Only the first element is tentatively explained; the rest of the name is unexplained, so the overall meaning is recorded as uncertain. The name is anchored by Saint Declan, described as a 5th-century missionary to the Déisi peoples of Ireland and the founder of the monastery at Ardmore.
Editorial confidence: uncertain
Linguistic roots
| Language | Form | Meaning |
|---|---|---|
| Old Irish | dag | good (likely first element) |
| Old Irish | Declán | unknown as a whole |
Popularity
Declan ranked #139 for boys in the United States in 2025 (Social Security Administration); Behind the Name reports the same 2025 US rank. Behind the Name attributes earlier American boosts to main characters in the films The Jackal (1997) and Leap Year (2010).
| Region | Year | Rank | Source |
|---|---|---|---|
| United States | 2025 | #139 | ssa-2025 |
Nicknames, variants, and related names
Nicknames: Dec
Variants: Deaglán, Declán
Related names: None documented.
What the name feels like
Declan is a two-syllable Irish name with a hard, confident consonant cluster in the middle that keeps it from sounding soft. It offers an Irish saint's pedigree without the spelling hurdles of Deaglán, which is likely part of its appeal to English-speaking parents.
Style tags: Irish, saint's name, two syllables, anglicized
Editorial interpretation: The style impressions above are editorial opinion, not linguistic fact. The nickname Dec is a natural short form, not a diminutive documented by Behind the Name. The etymology, the saint and the film-driven popularity notes come from Behind the Name.
If you like this name
Names that share Declan's Irish roots, its sound or its anglicized-Gaelic style. These groupings are editorial suggestions.
Similar by origin
- Ciarán
- Finnian
- Rónán
- Brendan
Similar by sound
Similar by style
Frequently asked questions
What does the name Declan mean?
The meaning of Declan is unknown. Behind the Name says the Old Irish form Declán likely begins with the prefix dag meaning "good", but the rest of the name is unexplained.
Is Declan an Irish name?
Yes. Declan is the anglicized form of Irish Deaglán, from Old Irish Declán. Saint Declan was a 5th-century missionary to the Déisi peoples of Ireland and founded the monastery at Ardmore.
How popular is Declan in the United States?
Declan ranked #139 among boys' names in the United States in 2025, according to Social Security Administration data. Behind the Name notes earlier boosts from characters in the films The Jackal (1997) and Leap Year (2010).
Sources
- Behind the Name: Meaning, origin and history of the name Declan — supports etymology, saint, film popularity notes, variants, pronunciation.
- U.S. Social Security Administration: Popular Baby Names — national data, year of birth 2025 — supports popularity.
