Jacob TremblayOrion (voice)
Paul Walter HauserDark (voice)
Angela BassettSweet Dreams (voice)
Colin HanksAdult Orion (voice)
Natasia DemetriouSleep (voice)
Golda RosheuvelUnexplained Noises (voice)
Nat FaxonInsomnia (voice)
Aparna NancherlaQuiet (voice)
Ike BarinholtzLight (voice)
Carla GuginoOrion's Mom (voice)
Matt DellapinaOrion's Dad (voice)
Nick KishiyamaTycho (voice)
Mia Akemi BrownHypatia (voice)
Shannon Chan-KentAdult Hypatia (voice)
Jack FisherRichie Panici (voice)
Werner HerzogNarrator (voice)
Sky AlexisLisa (voice)
Hira AmbrosinoWoman at the Drive-In (voice)
Yoshi AndoMan at the Drive-In (voice)
Larisa AsuajeMrs. Spinoza (voice)
Sean CharmatzIrene's Boss / Cucumber Dentist / Soda / Insomnia Guy 1 (voice)
Walt DohrnStray Cat / Insomnia Guy 2 (voice)
Ren HanamiAdult Sally (voice)
Amy HillIrene (voice)
Alyssa LeeIrene's Daughter / Insomnia Girl (voice)
Noah McCownScared Child (voice)
Shino NakamichiSally (voice)
Aliki TheofilopoulosIrene's Coworker / Mom / Juice Box / Insomnia Teacher (voice)
Toru UchikadoInsomnia Man (voice)