Children’s disclosures of sexual abuse during forensic interviews are fundamental to the investigation of cases. Research examining the relationship between age and disclosure has shown mixed results; the aim of the current study was to clarify and extend our knowledge by modeling linear, quadratic, and interaction effects of age on disclosure. Child sexual abuse reports made by children, their caregivers, or mandated reporters over a 12-month period to police in one state of Australia were examined. Of the 527 children (age range 3–16 years) offered a forensic interview, 81% disclosed abuse during it. The other 19% did not disclose or refused the interview. Age had both linear and quadratic effects, whereby disclosure increased with age until 11 years, after which disclosure decreased with age to 16 years. The effect of age on disclosure was moderated by five variables: abuse severity, the child–suspect relationship, suspects’ violence histories, delay of report to police, and children’s previous disclosures. Particular groups of children had lower likelihoods of disclosing abuse in forensic interviews than others, such as adolescents who alleged abuse against suspects with histories of violent offending. By identifying these groups, targeted strategies may be developed to help increase their disclosure rates.