Disordered eating frequently co-occurs with nonsuicidal self-injury (NSSI), and evidence suggests that the co-occurrence of these behaviors is associated with heightened emotion dysregulation. However, little is known about the relationship between restrictive eating and NSSI, and the significance of their co-occurrence. This study examined cross-sectional associations between self-reported restrictive eating, NSSI, and putative mechanisms of emotion regulation and interpersonal problems in a non-clinical sample of undergraduate students (N = 98, 80.6% female), using the Dietary Restriction Screener (Haynos & Fruzzetti, 2015), Deliberate Self-Harm Inventory (Gratz, 2001), Difficulties in Emotion Regulation Scale (Gratz & Roemer, 2006), and Inventory of Interpersonal Problems-Personality Disorders-25 (Kim & Pilkonis, 1999). Hierarchical logistic regression analyses indicated that restrictive eating was associated with NSSI above and beyond the influence of binge eating, purging, and relevant covariates (B = 2.04, p < 0.001). In addition, multivariate analyses of variance revealed that the co-occurrence of restrictive eating and NSSI was associated with greater difficulties accessing and implementing effective, rather than impulsive, emotion regulation strategies when distressed than either behavior alone (p < 0.001). Findings highlight the seriousness of restrictive eating even within a nonclinical sample, as it is associated with heightened probability of NSSI and clinical severity among those who engage in co-morbid NSSI. Healthcare providers are encouraged to screen for NSSI among individuals with restrictive eating. In addition, a focus on improving emotion regulation and interpersonal skills may enhance prevention and intervention efforts for individuals with co-occurring restrictive eating and NSSI behaviors.