The COVID-19 pandemic has brought to light the importance of not only improving the resilience of health systems to crises but also of ensuring their long-term sustainability. The Partnership for Health System Sustainability and Resilience (PHSSR) was established in 2020 with the goal of building more sustainable and resilient health systems around the world. One of the key objectives of PHSSR is to build knowledge, understanding, and consensus on the dimensions of health system sustainability and resilience, and how they can be improved. To achieve this goal, PHSSR focuses on seven key domains: Governance: the wide range of steering and rule-making related functions carried out by governments and decision-makers as they seek to achieve national health policy objectives. Financing: how health systems generate, pool, and allocate financial resources and pay for health services. Workforce: how health systems plan for, train, recruit, reward, and deploy their workforce, and shape the conditions in which health professionals work. Medicines and Technology: how health systems make use of medicines and (information) technologies in the delivery of health services. Service Delivery: how health services are organised and delivered, including ambulatory and hospital care, and public health. Population Health: how health systems address the social determinants of health and meet the needs and demands of the population. Environmental Sustainability: how health systems prevent and minimise their carbon footprint and the impacts of pollution on the population’s health. By examining each of these domains, PHSSR seeks to identify strengths, weaknesses, opportunities, and threats to health systems and to generate evidence-informed solutions and policy recommendations to improve sustainability and resilience.