Robin Williams
T.S. Garp

Mary Beth Hurt
Helen Holm

Glenn Close
Jenny Fields

John Lithgow
Roberta Muldoon

Hume Cronyn
Mr. Fields

Jessica Tandy
Mrs. Fields

Swoosie Kurtz
The Hooker

Brenda Currin
Pooh

Peter Michael Goetz
John Wolfe

Jenny Wright
Cushie

John Irving
Referee

Amanda Plummer
Ellen James

Bette Henritze
Woman Candidate

Katherine Borowitz
Rachel

Kate McGregor-Stewart
Real Estate Lady

Mark Soper
Michael Milton

Warren Berlinger
Stew Percy

Brandon Maggart
Ernie Holm

Ron Frazier
Stephen

Eve Gordon
Marge Tallworth

George Roy Hill
Pilot (uncredited)