This study examined suicide and self-harm trajectories in 180 individuals with BPD receiving dialectical behavior therapy or general psychiatric management in a randomized controlled trial. Suicide and self-harm behaviors were assessed at baseline, every four months throughout treatment, and every 6 months over 2 years of follow-up. Latent class growth mixture modeling identified suicide and self-harm trajectories. Multinomial logistic regression analyses examined baseline patient characteristics. Three latent subgroups were identified. The largest responded rapidly to treatment and sustained a favorable response post-discharge. The second progressed slowly during treatment but achieved and maintained a favorable response. A third subgroup showed a rapid favorable response during treatment, however symptoms returned to near baseline levels post-discharge. This third subgroup had higher baseline depression, emergency department visits, and unemployment. BPD patients with high baseline health care utilization, depression, and unemployment may benefit from modifications to treatment specifically targeting these issues.