Purpose. To determine whether a dialectical behavior therapy (DBT)-based journal-writing group is effective at increasing the emotion regulation abilities and decreasing depression and suicidal ideation in a sample of inpatient adolescent females. Method. Forty inpatient adolescent females completed surveys of emotion regulation, depression, and suicidal ideation (Toronto Alexithymia Scale (TAS-20), Difficulties in Emotion Regulation Scale (DERS), Beck Depression Inventory (BDI), & Suicide Probability Scale (SPS)) at pre- and post-intervention. Twenty-one adolescent females participated in the DBT-based journal-writing experimental group and nineteen adolescent females participated in the Treatment as usual control group. Results. Participants in the experimental group reported significant decreases in suicidal ideation and depressive symptoms and significant increases in emotion regulation abilities (BDI: t = 4.3, p = .000, DERS: t = 2.9, p = .009, TAS-20: t = 2.0, p = .058, SPS: z = -1.9, p = .053), whereas participants in the control group did not report significant change (BDI: t = 1.3, p = .198, TAS-20: t = 0.5, p = .649, DERS: t = 1.4, p = .187, SPS: z = -.1, p = .887). When changes in pre- to post-test scores were compared between the control group and the experimental group, significant results were found only for the BDI (t = -2.5, p = .019). Conclusion. A DBT-based journal-writing group is an effective way to decrease depressive symptoms and suicidal ideation and increase emotion regulation abilities in inpatient adolescent females and can be used in the future as a means to maximize treatment gains for adolescents on inpatient units.