According to FBI data, from 1991 to 2000, arrests of girls increased more (or decreased less) than arrests of boys for most types of offenses. By 2004, girls accounted for 30% of all juvenile arrests. However, questions remain about whether these trends reflect an actual increase in girls' delinquency or changes in societal responses to girls' behavior. A Girls Study Group was formed to establish a theoretical and empirical foundation to guide the development, testing, and dissemination of strategies to reduce or prevent girls' involvement in delinquency and violence. This report assesses the accuracy of claims that there is a significant rise in violent behavior among girls that has become a burgeoning national crisis. It examines the involvement of girls in violent activity (including whether such activity has increased relative to the increase for boys) and the contexts in which girls engage in violent behavior. Tables and figures. This is a print on demand report.