The Tsunami Warning Center Reference Guide aims to serve as a reference for countries that are establishing, maintaining, or enhancing existing tsunami warning centers as part of an overall end-to-end tsunami warning system. This guide describes a concept of operations for a National Tsunami Warning Center (NTWC) or Regional Tsunami Watch Provider (RTWP), including the key operational components of a tsunami warning center and the relationship between each component within a warning system. Lessons learned are incorporated from the two National Oceanic and Atmospheric Administration (NOAA) operational tsunami warning centers in Alaska and Hawaii, as well as from regional and national warning centers operated by France, Russia, and Japan. As a result, this document is a concept of operations (CONOPS) based on guidance established by the Intergovernmental Oceanographic Commission (IOC). Individuals who will find the information useful include, but are by no means limited to: international and national policy makers; national and local government preparedness officials; disaster responders, including NGOs; television, radio, and newspaper staff; and tsunami warning center staff. Download the guide here.