Immediately after WHO declared the COVID-19 outbreak to be a public health emergency of international concern, WHO offices in countries, territories and areas globally swiftly reorganized their operations to provide relevant guidance and support to governments to contain the spread of the SARS-CoV-2 virus, ensure uninterrupted provision of essential health services, save lives and protect the vulnerable.These case studies illustrate different aspects of WHO’s response to COVID-19 in countries, territories and areas and focus on successful interventions. They also highlight ongoing challenges and represent the experience of a diverse range of countries, each with different population health needs, health system development, and recourse levels.