Although prevalence studies show girls are more frequently sexually abused than boys, a significant proportion of boys also experience child sexual abuse (CSA). The challenges for public policy are amplified for boys due to less developed public and professional sensitisation to boys’ experiences, conceptions of masculinity, and less research on boys including into reporting trends and outcomes. We conducted a 20-year longitudinal time-trend analysis of government data to identify reporting trends and report outcomes for CSA in Victoria, Australia from 1993 to 2012. We stratified by child gender and reporter status. Results indicate a new sensitisation to CSA, especially for boys, although this trend was not stable. Marked change occurred in the last five years, likely influenced by major social and political events. Comparison over time revealed that from 1993 to 2012, the rate of reporting of boys increased 2.6-fold whereas there was a 1.5-fold increase for girls. Comparing genders, with regards to rate of reporting, in 1993, the sex ratio of girls to boys was 2:1, while by 2012 this ratio changed to 1.14:1. Reports by police and other mandated reporters accounted for the majority of the increase in reports over the 20-year period, suggesting unequal sensitisation. Positive report outcomes (i.e. substantiations, findings of harm, and referral to services) increased twelve-fold for boys, and nearly five-fold for girls, indicating the increased levels of reports were based in actual clinical need. Most of this increase occurred from 2009 to 2012, influenced by a compound of social, political and agency-related factors.