Lacey Chabert

as Eliza Thornberry (voice)

Tom Kane

as Darwin (voice)

Cree Summer

as Phaedra (Elephant) (voice)

Tim Curry

as Nigel Thornberry / Col. Radcliff Thornberry (voice)

Lynn Redgrave

as Cordelia Thornberry (voice)

Jodi Carlisle

as Marianne Thornberry (voice)

Danielle Harris

as Debbie Thornberry (voice)

Flea

as Donnie Thornberry (voice)