Rex vs Theodore

Baby Name Comparison — 2026

Popularity Comparison

Rex Rank #793
Theodore Rank #4

Theodore is more popular, ranked #4 vs #793 for Rex.

Popularity Over Time

Historical US popularity rank — lower number means more popular.

Middle Name Pairings

Rex ___

  • Rex James
  • Rex Oliver
  • Rex Arthur
  • Rex Henry
  • Rex William
  • Rex Theodore

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 Rex

Max Leo Augustus Vivienne Cordelia

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 Rex or Theodore more popular?

Theodore is more popular, ranked #4 compared to Rex at #793 in the United States.

What do Rex and Theodore mean?

Rex means "king" (Latin origin). Theodore means "divine gift" (Greek origin).

Are Rex and Theodore boy or girl names?

Rex is primarily a boy name. Theodore is primarily a boy name.

More Comparisons

Theodore vs Rex Rex vs Kaiser Rex vs Avyaan Rex vs Ahmad Rex vs Jase
← Full profile: Rex ← Full profile: Theodore Browse all baby names