Biliary tract cancers, including gallbladder cancer, intrahepatic, perihilar, and distal cholangiocarcinomas, although anatomically contiguous, represent a heterogeneous group of cancers with extensive biologic and genetic diversity. With early disease, surgical resection is the preferred option for all subtypes; however, relapse rates remain high, and survival outcomes are poor. Data to guide the use of adjuvant therapy have been limited to retrospective series, population-based studies, and meta-analyses, all with their associated limitations. The number of prospective trials ongoing or completed is increasing, and these results will ultimately dictate optimal treatment of this group of diseases. This review summarizes the data for adjuvant therapy in biliary tract cancers.