Introduction: Perinatal opioid use disorder (OUD) represents a maternal-child health crisis in the United States. Untreated, OUD is associated with maternal and neonatal morbidity due to infectious disease, polysubstance use, co-occurring mental health conditions, prematurity, neonatal opioid withdrawal, and maternal mortality from overdose. Although national guidelines exist to optimize perinatal care for women with OUD, wide variation persists in health care providers' experience caring for this population and in the quality of care delivered. Process:We conducted a pilot study to determine whether the use of a checklist summarizing best practice could improve perinatal care for women with OUD. Implementation was supported by a learning collaborative of maternity care providers at 8 diverse sites across Vermont, New Hampshire, and Maine. Outcomes before and after implementation were compared to determine whether practice change occurred.Outcomes: Data were collected from the records of 223 women with OUD who received prenatal care at pilot sites. All sites endorsed use of the checklist as a practice guide, and it was integrated in 78% of records reviewed. Across sites, significant improvement occurred in key elements of care, including increasing the proportion of women with access to the lifesaving drug naloxone (10.9% vs 36.3%, P Ͻ .001), receiving counseling about the benefits of breastfeeding (50.9% vs 72.0%, P Ͻ .01), and treating with nicotine replacement when indicated (9.1% vs 26.8%, P = .01). No significant change occurred in rates of prematurity, low birth weight, or breastfeeding at hospital discharge.Discussion: Implementation of a checklist to facilitate best practice in the care of pregnant women with OUD is feasible, acceptable to maternity care providers, and represents a promising approach to improving quality of care for this vulnerable population. Additional research is needed to determine whether improvement in quality can transform perinatal outcomes.