Biliary tract cancers (BTCs), including intrahepatic, perihilar and distal cholangiocarcinomas, and gallbladder cancers, are a heterogeneous cohort of tumors that tend to present with advanced stage and with high rates of recurrence after surgical resection. While liver-directed radiotherapy was traditionally restricted to the palliative setting given concerns over hepatotoxicity, modern radiotherapy techniques have enabled safe and effective treatment of a variety of hepatic tumors, thereby expanding the role of liver-directed radiotherapy in the management of BTCs. For resected BTCs, adjuvant chemoradiotherapy is recommended for patients with involved lymph nodes and positive resection margins. For patients with hilar cholangiocarcinomas, neoadjuvant chemoradiotherapy is recommended prior to orthotopic liver transplantation. Finally, for patients with unresectable disease, definitive radiotherapy in addition to systemic therapy represents a potential opportunity to maximize both local control and overall survival. In this review, we will discuss the evidence supporting the use of liver-directed radiotherapy for BTCs, as well as ongoing clinical investigations.