Horton Hatches the Egg is a 1942 American animated short film by Leon Schlesinger Productions, based on the 1940 book by Dr. Seuss, and released as part of Warner Bros.' Merrie Melodies series. The short was directed by Bob Clampett and was the first film adaptation based on a Seuss book.

Horton Hatches the Egg is a children's book written and illustrated by Theodor Geisel under the pen name Dr. Seuss and published in 1940 by Random House. The book tells the story of Horton the Elephant, who is tricked into sitting on a bird's egg while its mother, Mayzie, takes a permanent vacation to Palm Beach. Horton endures a number of hardships but persists, often stating, "I meant what I said, and I said what I meant. An elephant's faithful, one hundred percent!" Ultimately, the egg hatches, revealing an elephant-bird, a creature with a blend of Mayzie's and Horton's features.