Danny DeVito The Lorax (voice) Ed Helms Once-ler (voice) Zac Efron Ted Wiggins (voice) Rob Riggle Mr. Aloysius O'Hare (voice) Taylor Swift Audrey (voice) Jenny Slate Mrs. Wiggins (voice) Betty White Grammy Norma (voice) Nasim Pedrad Once-ler's Mom (voice) Joel Swetow 1st Marketing Guy (voice) Michael Beattie 2nd Marketing Guy (voice) Elmarie Wendel Aunt Grizelda (voice) Dave B. Mitchell 1st Commercial Guy (voice) Dempsey Pappion 2nd Commercial Guy (voice) Danny Cooksey Brett / Chet (voice) Stephen Tobolowsky Uncle Ubb (voice) Chris Renaud Forest Animals (voice) Sherry Lynn Additional Voices (voice) Jack Angel Additional Voices (voice)