Unlike male-on-female sexual assaults, little is known about the nature of male-on-male sexual assault, especially in terms of victim, offender and offence characteristics. The present paper systematically reviews the limited research into male-on-male sexual offences in order to ascertain the current state of knowledge with regards to these issues. An extensive search resulted in the identification of 15 empirical studies, with a total of 5,112 cases of male-onmale sexual assaults, for inclusion in the analyses. Findings revealed that, in the main, both victims and offenders of this type of offence tend to be young and heterosexual. Offenders tend to act alone during the assault and to be previously acquainted with the victim. Most male-on-male sexual assaults are violent in nature, taking place in either the victim's or the offender's home. Victims are subjected to various sexual acts, with anal penetration being the most frequent, and victims are frequently forced to perform oral sex on the offender. The implications of these findings, as well as limitations of the reviewed studies and directions for future research, are discussed.3