Despite the widespread prevalence of nonsuicidal self-injury (NSSI) among community-based samples, little is known about which self-injurers disclose their NSSI or the factors that promote disclosure among self-injurers. To address this gap in the literature, we examined whether disclosers could be differentiated from nondisclosers on the basis of NSSI characteristics (e.g. frequency of NSSI and severity of NSSI), NSSI motivations (e.g. interpersonal and intrapersonal motivations) and psychosocial factors (e.g. suicidal ideation and self-esteem). Participants consisted of a large sample of 268 self-injuring undergraduate students (Mage = 19.07 years, 70.3% women) at a Canadian university. Results indicated that 57% of self-injurers had never disclosed their NSSI to anyone. Self-injurers were most likely to disclose to peers and romantic partners. Logistic regression analyses revealed that pain during NSSI, severity of NSSI, interpersonal motivations for engaging in NSSI, higher suicidal ideation and higher friendship quality were all associated with a greater likelihood of NSSI disclosure. Our findings suggest that individuals with severe NSSI and suicidal ideation may be more likely to disclose. Moreover, our findings underscore the importance of equipping friends and romantic partners with effective responses to NSSI disclosures to promote more formal help-seeking behaviours among self-injurers. Copyright © 2014 John Wiley & Sons, Ltd.