This study assessed the economic evidence on the pharmacological and non-pharmacological management of infants with neonatal opioid withdrawal syndrome (NOWS). Six databases were searched up to October 2020 for peer-reviewed studies. After titles and abstracts were screened, 79 studies remained for full-text review, and finally, 8 studies were eligible for inclusion in the review. The methodological quality of included studies was assessed using the Drummond checklist. The review showed significant limitations in these studies, with one study being rated as good and the remaining seven studies as of poor quality. There are methodological issues that require addressing, including a lack of detail on cost categories, a robust investigation of uncertainty, and extending the time horizon to consider longer-term outcomes beyond the initial birth hospitalization. Despite these limitations, existing evidence suggests non-pharmacological strategies such as rooming-in were associated with a shorter hospital stay and a decreased need for pharmacological treatment, thereby lowering hospitalization costs. The review highlights the paucity of high-quality studies assessing the cost-effectiveness of intervention strategies for NOWS. There is also a lack of evidence on long-term outcomes associated with NOWS and the treatment of NOWS. The inclusion of economic analyses in future studies will provide evidence to inform policymakers on resource allocation decisions for this patient population.