Lorne Greene as Grandfather (voice)

Sammy Davis Jr. as Head Ratte (voice)

Margery Grey as Heidi (voice)

Pamelyn Ferdin as Klara (voice)

Michael Bell as Willie (voice)

Peter Cullen as Gruffle (voice)

Roger DeWitt as Peter (voice)

Richard Erdman as Grimm (voice)

Fritz Feld as Sebastian (voice)

Burr DeBenning as Herr Sessmann (voice)

Joan Gerber as Fräulein Rottenmeier (voice)

Virginia Gregg as Aunt Dete (voice)

Janet Waldo as Tinette (voice)

Frank Welker as Schnoddle/Hootie (voice)

Michael Winslow as Mountain (voice)

Sandie Hall as Chorus (voice)