Freddie Highmore character Jared Grace / Simon Grace
Mary-Louise Parker character Helen Grace
Nick Nolte character Mulgarath
Sarah Bolger character Mallory Grace
Andrew McCarthy character Richard Grace
Joan Plowright character Aunt Lucinda Spiderwick
David Strathairn character Arthur Spiderwick
Seth Rogen character Hogsqueal (voice)
Martin Short character Thimbletack (voice)
Jordy Benattar character Young Lucinda Spiderwick
Tod Fennell character Helen's Co-Worker
Mariah Inger character Nurse
Jeremy Lavalley character Tow Truck Driver
Lise Durocher-Viens character Mrs. Spiderwick
Tyler Patrick Jones character Additional Performer
Kyle Switzer character Additional Performer
Ron Perlman character Red Cap (voice) (uncredited)
