There is a need to delineate best practices for referring, assessing, and retaining students suspected of posttraumatic stress (PTS) and maladaptive grief (MG) in school-based treatment. Evidence-based risk-screening procedures should accurately include students who are appropriate for group treatment and exclude students who do not require treatment or who are better served by other forms of intervention and support. We described and evaluated the sequence of steps used to screen 7th- and 8th-grade students (N = 89) referred by school staff as candidates for an open trial of group-based Trauma and Grief Component Therapy for Adolescents (TGCTA; Saltzman et al., in press). We used t tests to compare included versus excluded students on PTS symptom and MG reaction scores (University of California at Los Angeles Posttraumatic Stress Disorder Reaction Index; Grief Screening Scale) during the group screen, individual interview, and treatment-implementation phases. Logistic regressions tested the incremental utility of including measures of both trauma exposure and related emotional and conduct problems (Strengths and Difficulties Questionnaire) in the screening battery. Results suggest that the group screen helped to detect mental health needs and that the individual interview further identified students with PTS and emotional problems. Conduct problems and trauma exposure predicted attrition among students who qualified for treatment. MG incrementally predicted students who advanced from the group screening to the individual interview, and trauma exposure incrementally predicted attrition from treatment. Findings yield implications for improving research and practice, including procedures for enhancing school-based referral, screening, assessment, and selection procedures.