Women and girls represent only a minority in the penitentiary system and in forensic mental health care. About 6%–10% of both prison and forensic psychiatric populations in Western countries comprise women (see for the most recent offi cial statistics in the UK w ww.gov. uk/government, in Canada w ww.statcan.gc.ca, and in the US w ww.bjs.gov) . However, there seems to be widespread agreement that in the past 20 years female offending has been on the rise, especially violent offending and particularly among young women ( Miller, Malone, and Dodge, 2010; M oretti, Catchpole, and Odgers, 2005) . Overall, a disproportionate growth of females entering the criminal justice system and forensic mental health care has been observed in many countries (for reviews, see Nicholls, Cruise, Greig, and Hinz, 2015; Odgers, Moretti, and Reppucci, 2005 ; Walmsley, 2015) . In addition, it should be noted that the ‘dark number’ for women is suggested to be bigger than for men. Offi cial prevalence rates of female offending might constitute an underestimation as women usually commit less reported offences, for example, domestic violence (N icholls, Greaves, Greig, and Moretti, 2015) . Furthermore, it has been found that – if apprehended – girls and women are treated more leniently by professionals and the criminal justice system. Generally, they receive lower prison sentences and are more often admitted to civil psychiatric institutions instead of receiving a prison sentence or mandatory forensic treatment after committing violence ( Javdani, Sadeh, and Verona, 2011 ; Jeffries, Fletcher, and Newbold, 2003 ). Hence, although female offenders compared to male offenders are a minority, female violence is a substantial problem that deserves more attention. Our understanding of female offenders is hindered by the general paucity of theoretical and empirical investigations of this population. In order to improve current treatment and assessment practices, our knowledge and understanding of female offenders should be enlarged and optimised (d e Vogel and Nicholls, 2016 ).