Many adolescent girls experience the death of a peer, which is often sudden and at times violent. These deaths are typically viewed as preventable, which can complicate the grief reactions of adolescent girls. The impact of peer death on adolescent girls involves a number of physical, emotional, social, and cognitive grief responses. Negative outcomes include school problems, depression, substance abuse, and suicidal ideation. This study examines the efficacy of the Adolescent Grief and Loss (AGL) group, a six-week group designed to address the needs of adolescent girls who have experienced the death of a peer within the past two years. The goal of the AGL group was to reduce or lessen physical, emotional, social, and cognitive responses to grief, and to foster mutual support and connection to others via various tasks associated with each group session. The AGL group was conducted in four different public high schools in Central Texas, with a sample size of 20 girls. A mixed methods design was utilized for this study, integrating both quantitative and qualitative research designs. The quantitative component employed a non-experimental simple time-series design, using two pre-test and three post-test time points. The qualitative component was based on a phenomenological analysis of adolescent grief and loss response, which included open-ended questions developed to capture each adolescent girl’s individual experience of peer death. Questions were also asked to elicit the girls’ experience of participating in the AGL group. The quantitative results of the study indicate that adolescent girls benefited from participation in the AGL group as evidenced by significantly reduced scores on the Loss Response List for all domains of physical, emotional, social, and cognitive grief responses. The qualitative findings yielded five overarching themes of experience of peer death: the story, physical reactions, emotional reactions, social reactions, and cognitive reactions. Integration of the quantitative and qualitative findings of this research study strongly support the benefits of providing a grief and loss group to adolescent girls who have been impacted by the experience of peer death. / text