These guidelines provide guidance on the diagnosis of HIV infection, the care of people living with HIV and the use of antiretroviral (ARV) drugs for treating and preventing HIV infection. They are structured along the continuum of HIV testing, prevention, treatment and care. This edition updates the 2016 WHO consolidated guidelines, including updates and guidelines produced since. The new UNAIDS 2025 targets place people living with HIV and communities at risk at the centre of the response and call for 95% of all people living with HIV knowing their HIV status, 95% who know their HIV-positive status initiating treatment and 95% of those receiving treatment having suppressed viral loads. They set clear targets for removing the societal and legal barriers to accessing services and emphasize the importance of integrating the HIV response with efforts to achieve universal health coverage as part of the Sustainable Development Goals. Several significant developments have occurred in HIV since the last consolidated guidelines were published in 2016. These include the introduction of dolutegravir, self-testing, scaling up of viral load and infant testing and new options for tuberculosis (TB) preventive therapy and for post-exposure prophylaxis. Advanced HIV disease has been recognized as a persistent challenge to reducing mortality, and differentiated approaches to service delivery have demonstrated benefit in supporting the delivery of effective quality care. New point-of-care viral load testing technologies offer further potential to expand this approach.