The 2018 FAO-OIE-WHO (Tripartite) zoonoses guide, “Taking A Multisectoral, One Health Approach: A Tripartite Guide to Addressing Zoonotic Diseases in Countries” (2018 TZG) is being jointly developed to provide member countries with practical guidance on OH approaches to build national mechanisms for multisectoral coordination, communication, and collaboration to address zoonotic disease threats at the animal-human-environment interface. The 2018 TZG updates and expands on the guidance in the one previous jointly-developed, zoonoses-specific guidance document: the 2008 Tripartite “Zoonotic Diseases: A Guide to Establishing Collaboration between Animal and Human Health Sectors at the Country Level”, developed in WHO South-East Asia Region and Western Pacific Region. The 2018 TZG supports building by countries of the resilience and capacity to address emerging and endemic zoonotic diseases such as avian influenza, rabies, Ebola, and Rift Valley fever, as well as food-borne diseases and antimicrobial resistance, and to minimize their impacts on health, livelihoods, and economies. It additionally supports country efforts to implement WHO International Health Regulations (2005) and OIE international standards, to address gaps identified through external and internal health system evaluations, and to achieve targets of the Sustainable Development Goals. The 2018 TZG provides relevant country ministries and agencies with lessons learned and good practices identified from country-level experiences in taking OH approaches for preparedness, prevention, detection and response to zoonotic disease threats, and provides guidance on multisectoral communication, coordination, and collaboration. It informs on regional and country-level OH activities and relevant unisectoral and multisectoral tools available for countries to use.