Jacob Tremblay
Orion (voice)

Paul Walter Hauser
Dark (voice)

Angela Bassett
Sweet Dreams (voice)

Colin Hanks
Adult Orion (voice)

Natasia Demetriou
Sleep (voice)

Golda Rosheuvel
Unexplained Noises (voice)

Nat Faxon
Insomnia (voice)

Aparna Nancherla
Quiet (voice)

Ike Barinholtz
Light (voice)

Carla Gugino
Orion's Mom (voice)

Matt Dellapina
Orion's Dad (voice)

Nick Kishiyama
Tycho (voice)

Shannon Chan-Kent
Adult Hypatia (voice)

Jack Fisher
Richie Panici (voice)

Werner Herzog
Narrator (voice)

Sky Alexis
Lisa (voice)

Hira Ambrosino
Woman at the Drive-In (voice)

Yoshi Ando
Man at the Drive-In (voice)

Sean Charmatz
Irene's Boss / Cucumber Dentist / Soda / Insomnia Guy 1 (voice)

Walt Dohrn
Stray Cat / Insomnia Guy 2 (voice)

Ren Hanami
Adult Sally (voice)

Amy Hill
Irene (voice)

Aliki Theofilopoulos
Irene's Coworker / Mom / Juice Box / Insomnia Teacher (voice)

Toru Uchikado
Insomnia Man (voice)