A collection of websites selected and archived by the National Library of Medicine on biomedical, clinical, cultural, and social aspects of HIV/AIDS in the early 21st century. Website captures began in 2016 and are ongoing. The collection’s principal themes are HIV treatment, HIV prevention, biomedical research on HIV/AIDS, clinical care for HIV patients, living with HIV, and social-cultural responses to HIV/AIDS. The collection includes websites for U.S. federal agencies, state public health HIV/AIDS departments, community organizations, international clinical trial and vaccine research sites, non-governmental organizations, advocacy groups, and a wide array of social media including blogs, YouTube videos, Facebook pages, Twitter feeds, and more.