Objective: Longitudinal data on adolescent self-injury are rare. Little is known regarding the associations between various forms of self-injurious thoughts and behaviors over time, particularly within community samples that are most relevant for prevention efforts. This study examined nonsuicidal self-injury (NSSI) as a time-invariant, prospective predictor of adolescent suicide ideation, threats or gestures, and attempts over a 2.5-year interval. Method: A diverse (55% female; 51% non-White) adolescent community sample (n = 399) reported depressive symptoms, frequency of NSSI, suicide ideation, threats or gestures, and attempts in 9th grade (i.e., baseline) and at 4 subsequent time points. Generalized estimating equations and logistic regressions were conducted to reveal the associations between baseline NSSI and the likelihood of each suicidal self-injury outcome postbaseline while controlling for depressive symptoms and related indices of suicidal self-injury as competing predictors. Results: Baseline NSSI was significantly, prospectively associated with elevated levels of suicide ideation and suicide attempts, but not threats or gestures. Neither gender nor ethnicity moderated results. Conclusions: Above and beyond established risk factors such as depressive symptoms and previous suicidality, adolescent NSSI may be an especially important factor to assess when determining risk for later suicidality. (Contains 4 tables.)