This guide is intended to build the capacity of publicly funded Opioid Treatment Programs (OTPs) to integrate Hepatitis C Virus (HCV) prevention and treatment services into their programs. The guide may also be useful for Federally Qualified Health Centers (FQHCs), community and healthcare coalitions, nonprofit organizations and other substance use disorder and HCV treatment providers. The opioid epidemic has resulted in significant increases in HCV among people who inject drugs, accounting for 23% of new infections. HCV is completely curable and testing and treatment are the path to cure. OTPs play a critical role in comprehensive approaches to addressing HCV and this guide is one tool to help.