Klaus

Jason Schwartzman

as Jesper (voice)

J.K. Simmons

as Klaus (voice)

Rashida Jones

as Alva (voice)

Joan Cusack

as Mrs. Krum (voice)

Norm Macdonald

as Mogens (voice)

Will Sasso

as Mr. Ellingboe (voice)

Sergio Pablos

as Pumpkin / Olaf (voice)

Mila Brener

as Ellingboe Girl 3 (voice)

Neda Margrethe Labba

as Margu (voice)

Sydney Brower

as Ellingboe Girl (voice)

Teddy Blum

as Small Ellingboe Boy (voice)

Julian Zane

as Krum Boy (voice)

Emma Shannon

as Creepy girl 1 (voice)

Kendall Joy Hall

as Annelise (voice)

Sky Alexis

as Ellingboe Girl 2 (voice)

Tucker Meek

as Ellingboe Boy / Krum Boy (voice)

Amanda Philipson

as Ellingboe Councilwoman (voice)

Finn Carr

as Ellingboe Boy 1 (voice)

Lucian Perez

as Krum Boy / Creepy Boy 2 (voice)

Emma Yarovinsky

as Little Krum Girl (voice)

Jaeden Bettencourt

as Krum Boy / Jesper Son (voice)

Hailey Hermida

as Krum Girl 1 (voice)

Evan Agos

as Ellingboe Boy (voice)

Leo Miller

as Ellinboe Boy 5 (voice)

Bailey Rae Fenderson

as Creepy Girl 2 (voice)

Ayden Soria

as Creepy Boy 1 (voice)

Reiulf Aleksandersen

as Adult Saami (voice)

Matthew McCann

as Additional Kids Voices (voice)

Hudson West

as Additional Kids Voices (voice)

Joaquin Obradors

as Boy (voice)