This study examined the efficacy of dialectical behavior therapy (DBT) in reducing behaviors commonly used as exclusion criteria for posttraumatic stress disorder (PTSD) treatment. The sample included 51 suicidal and/or self‐injuring women with borderline personality disorder (BPD), 26 (51%) of whom met criteria for PTSD. BPD clients with and without PTSD were equally likely to eliminate the exclusionary behaviors during 1 year of DBT. By posttreatment, 50–68% of the BPD clients with PTSD would have been suitable candidates for PTSD treatment. Borderline personality disorder clients with PTSD who began treatment with a greater number of recent suicide attempts and more severe PTSD were significantly less likely to become eligible for PTSD treatment.