A large number of female sex workers are children. Multiple studies demonstrate that up to 40% of women in prostitution started this work prior to age 18. In studies across India, Nepal, Thailand and Canada, young age at entry to sex work has been found to heighten vulnerability to physical and sexual violence victimisation in the context of prostitution, and relates to a two to fourfold increase in HIV infection. Although HIV risk reduction among adult female sex workers has been a major focus of HIV prevention efforts across the globe, no public health interventions, to date, have addressed the increased hazards and HIV risk faced by adolescent female sex workers. Beyond the structural barriers that limit access to this vulnerable group, historical tensions between HIV prevention and child protection agencies must be overcome in order to develop effective strategies to address this large scale yet little recognised human rights and HIV-related crisis.