The California Girls' Study focused on four counties: San Diego, Los Angeles, Alameda, and Marin. These counties represented diverse regions of the State; large, moderate, and relatively small juvenile justice systems; and varying approaches to the development of services for females. Information came from a review of 956 case files and from 193 structured interviews with females in county juvenile halls. Results revealed that the families of females in the juvenile justice system are fragmented by multiple and serious stressors, including poverty, death, violence, and an intergenerational pattern of incarceration. Ninety-two percent of the interviewed participants reported experiencing one or multiple forms of emotional, physical, or sexual abuse. They were vulnerable to similar victimization in the juvenile justice system. The vast majority were experiencing one or more serious physical or mental health problems. Ninety-three percent reported experiencing between one and three school failures. A majority were nonviolent offenders charged with relatively minor status, property, drug, and other offenses. Findings suggested the need for comprehensive, gender-competent services based on 12 guiding principles, starting with the creation of a balance between risk-focused and strength-enhancing approaches. Several program models embraced these guidelines and targeted specific issues in the study participants. Findings supported the development of a blueprint for a gender-specific and developmentally sequenced service and program continuum that can be tailored to different regional characteristics. Recommendations, model program profiles, figures, tables, footnotes, appended interview instrument and case form, and 52 references