In 2015, to advance the global and national response to antimicrobial resistance (AMR), the World Health Assembly issued resolution WHA68.7 calling for all Member States to develop AMR national action plans that address the five objectives of the World Health Organization Global Action Plan (GAP) by May 2017. The WHO GAP provides a framework to support countries in developing their national action plans on AMR. To operationalize and accelerate implementation of national action plans on AMR, WHO has developed a costing and budgeting tool and accompanying user guide. The purpose is to support countries in costing prioritized activities of an operational plan linked to their AMR national action plan, and identify existing funding and funding gaps to promote resource mobilization and sustainable implementation. The target audience of the publication are national policy makers and designated costing coordinators for national action plans on AMR.