Despite increasing attention on gender-specific programming for girls involved in the juvenile justice system, not much is known about the effectiveness of gender-specific programs. The authors review the evidence base for the effectiveness of programs for girls in custody or under supervision by examining the evaluation evidence for nine gender-specific programs (which exclusively target girls) and six gender-non-specific programs (which target both girls and boys). Through this process, the authors summarize the evidence of effectiveness available to researchers and practitioners, identify barriers to determining what programs work for adjudicated girls, and make recommendations for building a solid evidence base on what works for adjudicated girls. (Contains 1 table and 2 notes.)