Arthur is a 30-year-old child who will inherit $750 million if he complies with his family's demands and marries the woman of their choosing.

Dudley Moore
as Arthur Bach

Liza Minnelli
as Linda Marolla

John Gielgud
as Hobson

Geraldine Fitzgerald
as Martha Bach

Jill Eikenberry
as Susan Johnson

Stephen Elliott
as Burt Johnson

Ted Ross
as Bitterman

Barney Martin
as Ralph Marolla

Thomas Barbour
as Stanford Bach

Anne DeSalvo
as Gloria