Danny DeVito The Lorax (voice)
Zac Efron Ted Wiggins (voice)
Taylor Swift Audrey (voice)
Stephen Tobolowsky Uncle Ubb (voice)
Dr. Seuss Book
Betty White Grammy Norma (voice)
Ed Helms Once-ler (voice)
Jenny Slate Mrs. Wiggins (voice)
Randy Thom Sound Designer, Sound Re-Recording Mixer, Supervising Sound Editor
Kyle Balda Co-Director
Cinco Paul Executive Producer, Songs, Screenplay
Nasim Pedrad Once-ler's Mom (voice)
Jess Harnell Additional Voices (voice)
Laraine Newman Additional Voices (voice)
Rob Riggle Mr. Aloysius O'Hare (voice)
Debi Derryberry Additional Voices (voice)
Jack Angel Additional Voices (voice)
Bob Bergen Additional Voices (voice)
Ken Daurio Executive Producer, Screenplay
Danny Cooksey Brett / Chet (voice)
Jim Ward Additional Voices (voice)
Mickie McGowan Additional Voices (voice)
John Powell Original Music Composer, Songs
Bill Farmer Additional Voices (voice)
Gary Rizzo Sound Re-Recording Mixer
Mona Marshall Additional Voices (voice)
Jan Rabson Additional Voices (voice)
Daniel Laurie ADR Supervisor, Dialogue Editor
Danny Mann Additional Voices (voice)
John Cygan Additional Voices (voice)
Chris Meledandri Producer
Dennis Leonard Supervising Sound Editor
Joel Swetow 1st Marketing Guy (voice)
Chris Renaud Director, Forest Animals (voice)
Yarrow Cheney Production Design
Sherry Lynn Additional Voices (voice)
Fletcher Sheridan Cy (voice)
Dave B. Mitchell 1st Commercial Guy (voice)
Dempsey Pappion 2nd Commercial Guy (voice)
Carter Goodrich Character Designer
Michael Beattie 2nd Marketing Guy (voice)
Ken Schretzmann Editor
Steven Liu Editor
Mitja Rabar Animation
Elmarie Wendel Aunt Grizelda (voice)
Fabrice Joubert Animation
Claire Dodgson Editor
Claira Nicole Titman Additional Voices (voice)
Catherine Catie Lee Lighting Artist
Eric Guillon Character Designer
Audrey Geisel Executive Producer
Janet Healey Producer
Massimo Ruberto Music Supervisor