- Act 1
-
- "Overture" – Orchestra
- "Oh, The Thinks You Can Think!" – Company except The Grinch and Vlad Vladikoff
- "Our Story Begins"^ – The Cat and JoJo
- "Horton Hears A Who!"* – Bird Girls, Horton and Citizens of the Jungle of Nool
- "Biggest Blame Fool" – Sour Kangaroo, Young Kangaroo, Horton, Wickersham Brothers, Bird Girls, Gertrude McFuzz, Mayzie LaBird, Citizens of the Jungle, Jojo and The Cat
- "Here on Who" – The Mayor, Mrs. Mayor, The Grinch, Whos, and Horton
- "A Day for the Cat in the Hat" – The Cat, Jojo, and Cat's Helpers
- "It's Possible (In McElligot's Pool)"* – JoJo, The Cat and Fish
- "How To Raise A Child" – The Mayor and Mrs. Mayor
- "The Military" – General Genghis Khan Schmitz, The Mayor, Mrs. Mayor, JoJo and Cadets
- "Alone In The Universe" – Horton and JoJo
- "The One Feather Tail of Miss Gertrude McFuzz" – Gertrude
- "Amayzing Mayzie" – Mayzie LaBird, Gertrude, and the Bird Girls
- "Amazing Gertrude" – Gertrude, and Bird Girls
- "Monkey Around" – Wickersham Brothers and Horton
- "Chasing the Whos"* – Horton, Sour Kangaroo, Young Kangaroo, Bird Girls, Wickersham Brothers, The Cat, Vlad Vladikoff and Whos
- "How Lucky You Are" – The Cat, Whos
- "Notice Me, Horton" – Gertrude McFuzz and Horton
- "How Lucky You Are" (Reprise) – Mayzie LaBird, Horton
- "Horton Sits on the Egg" – Full Company
|
- Act 2
-
- "Entr'acte"^ – Orchestra
- "Our Story Resumes"^ – The Cat, JoJo, Horton, Gertrude McFuzz, General Genghis Khan Schmitz, Bird Girls, and Hunters
- "Egg, Nest, and Tree"* – Sour Kangaroo, Bird Girls, Wickersham Brothers, The Cat, and Hunters
- "The Circus McGurkus"^ – The Cat, Horton, and Circus Animals
- "Mayzie in Palm Beach"^ – Mayzie LaBird, The Cat and Horton
- "Amayzing Horton" – Mayzie LaBird and Horton
- "Alone in the Universe" (Reprise) – Horton
- "Solla Sollew" – Horton, The Mayor, Mrs. Mayor, JoJo, and Circus McGurkus Animals and Performers
- "The Butter Battle"^ – JoJo, General Genghis Khan Schmitz, and Cadets
- "The Grinch Carved the Roast Beast"^ – The Grinch, The Mayor, Mrs. Mayor, Cindy Lou Who, Max the Dog, and Whos
- "Havin' a Hunch"* – The Cat, JoJo, Hunches and Cat's Helpers
- "All For You" – Gertrude, Horton and Bird Girls
- "The People Versus Horton The Elephant"* – Principals except Mayzie
- "Finale" / "Oh, the Thinks You Can Think!" – Full Company
- "Curtain Call" / "Green Eggs And Ham" – Full Company
|