OBJECTIVE: To examine whether self-stigma of seeking psychological help and being male would be associated with an increased likelihood of having an undiagnosed eating disorder. METHOD: A multi-national sample of 360 individuals with diagnosed eating disorders and 125 individuals with undiagnosed eating disorders were recruited. Logistic regression was used to identify variables affecting the likelihood of having an undiagnosed eating disorder, including sex, self-stigma of seeking psychological help, and perceived stigma of having a mental illness, controlling for a broad range of covariates. RESULTS: Being male and reporting greater self-stigma of seeking psychological help was independently associated with an increased likelihood of being undiagnosed. Further, the association between self-stigma of seeking psychological help and increased likelihood of being undiagnosed was significantly stronger for males than for females. DISCUSSION: Perceived stigma associated with help-seeking may be a salient barrier to treatment for eating disorders-particularly among male sufferers.