The emergence of the internet has added a new dimension to sexual crimes as the sexual exploitation of minors can now be captured with digital photography and disseminated worldwide, while access to potential victims often takes place in what appears to be complete anonymity. This chapter discusses this international and ever-expanding phenomenon by exploring the different forms of sexual offending behaviors committed through the internet, ranging from its use to download and upload child sexual exploitation material, to engage adolescents in sexual communications and virtual activities, or to arrange sexual offenses against minors with others. The scope of the phenomenon is addressed with international statistics and the presentation of online sexual offenders’ profiles. Considerations for online sexual offenders’ risk assessment, treatment, and police interventions are also discussed, as well as ongoing prevention and research initiatives.