This chapter explores the psychology behind child sexual offending. The chapter commences by highlighting some common misconceptions concerning child sexual offenders. The underresearched area of female child sexual offenders is also discussed, followed by the theories used to explain and interpret child sexual offending, and the crime scripts held by child sexual offenders. The ever-advancing issue of online child predators concludes the chapter. This chapter highlights that child sexual offenders are not a homogenous group of individuals; further, a multifactorial approach needs to be used when understanding the behavior and cognitions in the lead up to, and during, the offending event.