During a household survey in Tanzania, a nationally representative sample of females and males aged 13-24 years reported any experiences of sexual violence that occurred before the age of 18 years. The authors explore the prevalence, circumstances, and health outcomes associated with childhood sexual violence. The results suggest that violence against children in Tanzania is pervasive, with roughly three in 10 females and one in eight males experiencing some form of childhood sexual violence, and its health consequences are severe. Results are being used by the Tanzanian government to implement a National Plan of Action.