Objective: To investigate near-term risk for self-injurious urges, we evaluated how within-person changes in internalizing and externalizing negative affect, as well as interpersonal rejection and criticism, impact subsequent nonsuicidal self-injury (NSSI) and suicide urges in daily life. Method: Young adult women (N = 62) from an ongoing community cohort study with past-year self-injurious thoughts completed a 21-day ecological momentary assessment protocol. We used multilevel path analyses to model within-person effects of negative affect and interpersonal stress on subsequent suicide and NSSI urges within several hours. Results: When modeled simultaneously, within-person changes in internalizing, but not externalizing, negative affect predicted later self-injurious urges. Rejection and criticism predicted later self-injurious urges, with rejection showing a unique relationship to NSSI urges specifically. Effects of rejection and criticism on later NSSI and suicide urges were mediated by internalizing negative affect; rejection also retained a significant direct effect on NSSI urges. Conclusion: Interpersonal stressors may be potent near-term risk factors for self-injurious urges by increasing internalizing negative affect among vulnerable individuals. The direct role of rejection and criticism on self-injurious urges is less clear, particularly for suicide. These findings have implications for understanding processes underlying self-injurious urges, as well as designing real-time interventions for these experiences in daily life.