Partial hospital programs (PHPs) are a vital mental health service for youth at risk for suicide. Yet, few studies have examined trajectories of suicidal ideation and depressive symptoms, two important risk factors for suicidal behavior, over the course of care. Moreover, little is known about factors that may impact these trajectories among youth in PHPs. The present study examined trajectories of suicidal ideation and depressive symptoms, as well as clinical and demographic predictors of these changes, among youth enrolled in two PHPs. A sample of 253 youth (Mage = 15.3; SD = 1.4; range = 12-18; 68.8% female; 63.2% White; 75.1% non-Hispanic/Latino/a/x) completed repeated measures of suicidal ideation severity and depressive symptoms during treatment. Trajectories of these outcomes were examined using two separate latent growth models. Recent history of self-injurious behaviors and demographics were tested as predictors of trajectories using a taxonomic approach. Overall, suicidal ideation and depressive symptoms declined over the course of care. Sex, history of self-injury, and sexual identity were associated with variability in one or both trajectories of change. Results suggest individual variability in the rate of change among youth in PHPs. Such information may be used to aid in treatment planning and quality improvement efforts within PHPs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).