Objective Presently, little is known about what factors predict adolescent psychiatric rehospitalization. Thus, the present study tested whether a battery of demographic and clinical characteristics predicted readmission within 6 months of discharge. Methods Participants were 165 adolescents (112 females) aged 13–19 years (mean = 15.61, SD = 1.48) admitted to an acute residential treatment program between November 25, 2013, and November 18, 2014. Patients met diagnostic criteria (DSM-IV-TR) for current major depressive disorder or dysthymia. At admission, participants completed a battery of clinical interviews and questionnaires assessing demographics, early life stress, comorbid diagnoses, psychiatric symptoms, suicidality, self-injury, and risky behavior engagement. At discharge, psychiatric symptoms were reassessed. Readmission to the same residential service was monitored over a 6-month period following discharge. Results Overall, 12.1% of adolescents were rehospitalized. We conducted a series of Cox regression survival analyses to test demographic and clinical predictors of patients’ time to readmission. More frequent self-injurious behaviors in the month prior to hospitalization was significantly associated with a more rapid time to rehospitalization (β = 0.05, SE = .02, Wald1 = 4.35, P = .037, OR = 1.05, 95% CI = 1.003–1.10). Conclusions It is critical to more effectively manage self-injury during the treatment of depressed adolescents, as this is the strongest predictor of later rehospitalization.