Jared Grace / Simon Grace

Freddie Highmore

Acting

Mallory Grace

Sarah Bolger

Acting

Arthur Spiderwick

David Strathairn

Acting

Helen Grace

Mary-Louise Parker

Acting

Mulgarath

Nick Nolte

Acting

Aunt Lucinda Spiderwick

Joan Plowright

Acting

Richard Grace

Andrew McCarthy

Acting

Hogsqueal (voice)

Seth Rogen

Acting

Thimbletack (voice)

Martin Short

Acting

Young Lucinda Spiderwick

Jordy Benattar

Acting

Mrs. Spiderwick

Lise Durocher-Viens

Acting

Helen's Co-Worker

Tod Fennell

Acting

Nurse

Mariah Inger

Acting

Tow Truck Driver

Jeremy Lavalley

Crew

Additional Performer

Kyle Switzer

Acting

Additional Performer

Tyler Patrick Jones

Acting

Red Cap (voice) (uncredited)

Ron Perlman

Acting