Globally, trans communities are among the most heavily impacted by HIV, yet they are among the least recognized within policy, the least served by programs, and the least supported by funding at national, regional, and international levels. Available data indicate a significant HIV burden within trans communities. A series of interwoven factors contribute to vulnerability, including biological, behavioural, structural and social determinants of health. The recent UNAIDS 2016–2021 Strategy, On the Fast-Track to End AIDS , identifies trans people as one of the key populations requiring specific attention.