Objectives This study examines aspects of healthcare professionals’ knowledge and attitudes about eating disorders (EDs), which might impede the effective detection or treatment of EDs in Ireland. Methods A total of 1,916 healthcare professionals were invited to participate in a web-based survey. Participants were randomly allocated to view one of five vignettes depicting a young person with symptoms consistent with anorexia nervosa, bulimia nervosa, binge-eating disorder, depression or type 1 diabetes. Study-specific questions examined participants’ responses to the vignettes and ED knowledge and experience. Results In total, 171 clinicians responded (9% response rate). Participants had an average of 15.8 years of clinical experience (s.d.=9.2) and included psychiatrists, GPs, psychologists and counsellors. Although participants’ knowledge of EDs was moderately good overall, responses showed poor recognition of the symptoms of EDs compared with depression [χ2 (4, n=127)=20.17, p<0.001]. Participants viewed EDs as chronic disorders that primarily affected females. Participants believed that clinicians like working with patients with depression and diabetes more than with AN patients [F (4,101)=5.11, p=0.001]. Among the professionals surveyed, psychiatrists were the most knowledgeable about EDs [F (4,82)=9.18, p<0.001], and were more confident in their ability to diagnose and treat EDs than professionals of all other disciplines, except psychologists [F (4,85)=8.99, p<0.001]. Psychiatrists were also the most pessimistic about ED patients’ long-term life prospects [χ2 (4, n=65)=15.84, p=0.003]. Conclusions This study recommends that specific attention should be given to EDs in professional educational programmes across healthcare disciplines. This training should not be restricted to improving healthcare professionals’ knowledge of EDs, but should also strive to increase service-providers’ awareness of how their own potentially stigmatising attitudes can undermine engagement with treatment.