Killian vs Theodore

Baby Name Comparison — 2026

Killian

Boy #370 Most Popular 3 Syllables

Meaning

"associated with the church"

Origin: Irish Gaelic

Cultural Roots

Irish French American English

Quick Stats

Popularity Rank
#370
Total SSA Count
884
Syllables
3
Formality
Moderate
Nicknames
Killy, Kill, Ian

Playground Safety Score

✓ All Clear
Full profile for Killian →

Popularity Comparison

Killian Rank #370
Theodore Rank #4

Theodore is more popular, ranked #4 vs #370 for Killian.

Popularity Over Time

Historical US popularity rank — lower number means more popular.

Middle Name Pairings

Killian ___

  • Killian James
  • Killian Patrick
  • Killian Thomas
  • Killian Finn
  • Killian Rory
  • Killian Sean

Theodore ___

  • Theodore James
  • Theodore William
  • Theodore Alexander
  • Theodore John
  • Theodore Henry
  • Theodore Arthur

Sibling Name Ideas

Names that pair well as siblings.

If you choose Killian

Cormac Riordan Aoife Declan Niamh

If you choose Theodore

Olivia Charlotte Amelia Eleanor Oliver

Which Name Fits Your Family?

Answer 3 quick questions and we'll help you decide.

1. Which style feels more like your family?

Frequently Asked Questions

Is Killian or Theodore more popular?

Theodore is more popular, ranked #4 compared to Killian at #370 in the United States.

What do Killian and Theodore mean?

Killian means "associated with the church" (Irish Gaelic origin). Theodore means "divine gift" (Greek origin).

Are Killian and Theodore boy or girl names?

Killian is primarily a boy name. Theodore is primarily a boy name.

More Comparisons

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← Full profile: Killian ← Full profile: Theodore Browse all baby names