The prevalence of suicidal behaviors in adolescents remains unacceptably high. Reviews of published randomized controlled trials (RCTs) for adolescent suicidality conclude that treatments to date have been minimally efficacious. The preponderance of interventions focus on crisis intervention, underlying psychiatric disorders, regulating negative affect and reducing cognitive distortions. However, our pilot work and other recent data suggest the importance of considering how low positive affectivity contributes to suicide risk independent of other risk factors and may be another mechanism that leads to suicidal behaviors. Our model is based on Fredrickson's empirically-supported Broaden and Build model which asserts that the function of positive affect (PA) includes helping individuals thrive by improving social supports, problem-solving, and personal resilience. Each of these areas is instrumental in decreasing suicidal behavior. We propose that PA increases survival directly by decreasing suicidal ideation and indirectly by increasing social support and problem-solving. In this R34 treatment development grant we seek to develop a novel, individual skills-based, PA intervention, delivered adjunctively to treatment as usual (TAU), targeting the highest risk adolescents - those hospitalized due to suicide risk. We focus on three strategies that have been demonstrated to increase sustainable (vs. transient) PA in community and depressed adults: meditation, gratitude, and savoring. There are several ways to practice each strategy; we take into account patient preferences in a personalized approach in which patients select the practice(s) that fits best with their needs and circumstances. We propose using multiple means of intervention delivery that includes text messaging, to reinforce in-vivo practice. Our intervention, Skills To Enhance Positivity Program (STEP) includes two phases: a) in-person phase consisting of 3 individual in-person sessions and 1 joint parent session during the inpatient hospital stay to teach positive affect skills and develop a personalized intervention; b) remote delivery phase which consists of weekly telephone booster calls and daily text messages over 4 weeks post-discharge. The phone calls will be used to review or adjust personalized intervention components and reinforce use of skills. The text messages will include self-scripted reminders to practice skills and links to online resources. STEP will be tested in an open trial with 20 participants, and after further revision, in a pilot RCT, compared to TAU in a sample of 50 adolescents. The primary goal of this intervention is for patients to increase positive affect by incorporating skills and practices into their normal home-based routines, which we believe will lead to increases in problem-solving and social support and decreases in suicidal ideation. This is a novel intervention for a high-risk acute population via a different mechanism (i.e. PA), and conceptually distinct from other empirically examined theoretical approaches.