Improvements in water sanitation and hygiene (WASH) and wastewater management in all sectors are critical elements of preventing infections and reducing the spread of antimicrobial resistance (AMR) as identified in the Global Action Plan to combat AMR. Yet, at present, WASH and wastewater management actors and improvement actions are under-represented in AMR multi-stakeholder platforms and national action plans (NAPs). This WHO/FAO/OIE technical brief on WASH and wastewater management to reduce the spread of AMR provides a summary of evidence and rationale for WASH and wastewater actions within AMR NAPs and sector specific policy to combat AMR. Evidence and actions are presented in the domains of; coordination and leadership, households and communities, health care facilities, animal and plant production, manufacturing of antimicrobials, and surveillance and research.