The evidence is clear that child sexual abuse is a public health concern internationally. Prevention of child sexual abuse requires a variety of interventions including those that stop individuals from either sexually assaulting a child or viewing sexually abusive online images. In contrast, most current approaches internationally focus on criminal justice strategies aimed at preventing reoffending rather than stopping the first offence. Additionally, and albeit there is a general paucity of relevant scholarship, there are few signs of countries adopting coherent, unified and evidence-based strategies to prevent individuals at risk of harming a child becoming actual or repeat offenders. The focus of interventions to date is largely on prevention at the tertiary end. Understanding and adopting an integrated public health approach represents an opportunity to incorporate a range of primary, secondary and tertiary prevention interventions and develop comprehensive prevention strategies at local, national, or international levels. A comprehensive approach to prevention targeted at stopping offending in the first place is required, and it needs to be able to recognise the complex nature of offending and the diversity therein. Research shows that those who harm children are diverse in their age and gender, the children they sexually abuse—intra-familial/extra-familial, prepubescent/pubescent, peer/younger children, male or female—and the type of abuse—contact, non-contact, or online. Preventing child sexual abuse is complex and requires more than an ad hoc collection of unrelated programs, if it is to succeed. This paper synthesises and integrates the disparate scholarly literature on the potential and actual perpetrators of child sexual abuse and responses to and prevention of such abuse. It recommends an increased focus on primary prevention within a comprehensive public health approach as a conceptual framework to prevent the occurrence of child sexual abuse. A systems approach is taken to develop the proposed conceptual framework.