Supporting the National Action Plan for Antimicrobial Resistance (SNAP-AMR) in Tanzania Antimicrobial resistance (AMR), the ability of bacteria to resist the effect of drugs, is a threat to human and animal health in resource rich nations like the UK and low and middle income countries like the United Republic of Tanzania. In Tanzania, as in many low and middle income countries, the AMR problem is compounded by the fact that people and livestock often live close together and widespread use of antimicrobials in both. In response to a global call to action from the World Health Organisation, Tanzania has created an ambitious National Action Plan to combat AMR, including improving awareness and understanding of the AMR problem among policy makers, professionals and the public and enhancing surveillance, research, infection prevention and antimicrobial stewardship in people and livestock. Successful implementation of the NAP is challenged by lack of human and financial resources, making prioritisation of activities and interventions an essential component of an effective and efficient campaign to control AMR.  Our research will provide new evidence to support this prioritisation and targeting, taking an approach that recognises that individuals are part of a larger system and that behaviour of professionals and the public may depend on policy, regulations or knowledge, but also on cultural background, social norms and access to medical, veterinary or diagnostic infrastructure and drugs. Our team of UK and Tanzania-based researchers and policy experts will take an interdisciplinary approach, working with a wide range of biological and social scientists as well as health professionals and community members, to provide novel insights into cultural, socio-economic and biological drivers of antimicrobial use (AMU) in hospitals and the community and in contextually appropriate methods of communication around those issues.  The origin of AMR problems can be described as hospital-, community- or livestock-associated so we will work with doctors and nurses, householders and patients, and veterinarians and livestock keepers as well as (in)formal drug providers and other stakeholders to investigate knowledges, beliefs, attitudes and practices around health and AMU/AMR. We will compare health care settings (health centres, district, regional and referral hospitals) and livestock keeping communities (Chagga, Masaai and Sukuma) to reflect a range of professional and cultural contexts. Using focus group discussions, questionnaires and interviews, we will examine factors that influence prescribing and use of antimicrobials and through choice experiments we will examine how changes in e.g. knowledges, social norms or access might change such behaviour. To complement the socio-economic investigations, we will use DNA-sequencing of hospital -, community - or livestock-associate bacteria in combination with mathematical modelling approaches to establish the relative contribution of different sources and transmission routes to the clinical and economic burden of AMR. The combination of insight into the drivers and relative importance of behaviours that may contribute to the AMR problem provides a unique opportunity to identify and prioritise levers of behavioural change to reduce AMU and limit the risk and impact of AMR.  Finally but importantly, we will work with policy makers, professionals and the public to design context-specific messages and methods to communicate AMR awareness and infection prevention and control messages in hospitals and community settings, and evaluate the impact of those communication campaigns using a combination of the social and biological sciences methods described above. The combined outcomes of our research will help priority setting in AMR control by identifying the settings where change is practicable and cost-effective. It will inform implementation of the National Action Plan in Tanzania and serve as a generalisable transdisciplinary model of AMR control in low and middle income country settings. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.