A male pediatric patient with elevated liver enzyme and bile acid levels, bile duct hypoplasia, mild liver fibrosis, and pruritus was initially diagnosed with progressive familial intrahepatic cholestasis. The patient did not respond to treatments of ursodeoxycholic acid and naltrexone. Subsequent treatment with odevixibat resulted in improvements in serum bile acid levels and pruritus within a few weeks of initiation. During the course of odevixibat treatment, genetic testing results and additional clinical findings indicated a diagnosis of Alagille syndrome, a condition that shares some clinical features with progressive familial intrahepatic cholestasis. Odevixibat treatment was continued off label, during which time the patient’s serum bile acid levels dropped to within the normal limit and pruritus was completely ameliorated. This report suggests odevixibat may be an effective treatment option for Alagille syndrome.