OBJECTIVE Subthreshold phototherapy use is common in infants with hyperbilirubinemia but leads to overtreatment of safe bilirubin levels. Coincident with publication of the 2022 American Academy of Pediatrics neonatal hyperbilirubinemia guidelines, we formed a quality improvement (QI) collaborative with the aim to reduce inpatient subthreshold phototherapy use to 10% of all phototherapy encounters over 12 months. METHODS Our QI collaborative included 146 hospitals across North America. Sites sub