Cillian vs Theodore

Baby Name Comparison — 2026

Popularity Comparison

Cillian Rank #464
Theodore Rank #4

Theodore is more popular, ranked #4 vs #464 for Cillian.

Popularity Over Time

Historical US popularity rank — lower number means more popular.

Middle Name Pairings

Cillian ___

  • Cillian James
  • Cillian Patrick
  • Cillian Michael
  • Cillian Finn
  • Cillian Declan
  • Cillian Joseph

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 Cillian

Declan Finn Conor Siobhan Saoirse

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 Cillian or Theodore more popular?

Theodore is more popular, ranked #4 compared to Cillian at #464 in the United States.

What do Cillian and Theodore mean?

Cillian means "strife, war" (Old Irish origin). Theodore means "divine gift" (Greek origin).

Are Cillian and Theodore boy or girl names?

Cillian is primarily a boy name. Theodore is primarily a boy name.

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