Danny DeVito as the Lorax Ed Helms as the Once - ler. Neither the book nor the TV special reveal the Once - ler 's face, but instead throughout the book, the Once - ler is pictured by what appears to be green arms and yellow eyes. The filmmakers used that as the basis for the Once - ler 's character design. They interpreted the Once - ler as a human, and also featured his green gloves and showed his face for the first time in this film. Zac Efron as Theodore "Ted '' Wiggins, an idealistic 12 - year - old boy. He is named after the author of the book, Dr. Seuss (Theodor Geisel). Taylor Swift as Audrey, Ted 's love interest. She is named after Audrey Geisel, Dr. Seuss ' wife. Betty White as Grammy Norma, Ted 's wise - cracking grandmother. Rob Riggle as Aloysius O'Hare, the greedy mayor of Thneedville and head of the "O'Hare Air '' company that supplies fresh air to Thneedville residents. Jenny Slate as Mrs. Wiggins, Ted 's neurotic mother. Nasim Pedrad as the Once - ler 's mother. Stephen Tobolowsky as Uncle Ubb, the Once - ler 's uncle. Elmarie Wendel as Aunt Grizelda, the Once - ler 's aunt. Danny Cooksey as Brett and Chet, the Once - ler 's twin brothers. Fletcher Sheridan (uncredited) as Cy, the O'Hare Air delivery guy Chris Renaud as Assorted forest animals
who did zac efron voice in the lorax
Theodore "Ted '' Wiggins