Sullivan vs Theodore

Baby Name Comparison — 2026

Sullivan

Boy #340 Most Popular 3 Syllables

Meaning

"descendant of the dark one"

Origin: Irish Gaelic

Cultural Roots

Irish American English

Quick Stats

Popularity Rank
#340
Total SSA Count
1,011
Syllables
3
Formality
Moderate
Nicknames
Sully, Van

Playground Safety Score

✓ All Clear
Full profile for Sullivan →

Popularity Comparison

Sullivan Rank #340
Theodore Rank #4

Theodore is more popular, ranked #4 vs #340 for Sullivan.

Popularity Over Time

Historical US popularity rank — lower number means more popular.

Middle Name Pairings

Sullivan ___

  • Sullivan James
  • Sullivan Patrick
  • Sullivan Thomas
  • Sullivan Reid
  • Sullivan Finn
  • Sullivan Grant

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 Sullivan

Finnegan Declan Bridget Nora Callum

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 Sullivan or Theodore more popular?

Theodore is more popular, ranked #4 compared to Sullivan at #340 in the United States.

What do Sullivan and Theodore mean?

Sullivan means "descendant of the dark one" (Irish Gaelic origin). Theodore means "divine gift" (Greek origin).

Are Sullivan and Theodore boy or girl names?

Sullivan is primarily a boy name. Theodore is primarily a boy name.

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