A number of psychiatric illnesses have been recognized to have some level of insight deficits, including developmental disorders, such as Asperger's Syndrome (ASP). However insight into illness has not been empirically investigated in ASP and little research has examined how individuals with ASP view their deficits. This is the first study to assess insight and the relationship between insight and externalizing bias (EB) in ASP. Participants with ASP (n = 21) and healthy controls (n = 24) were recruited. Attributional style was assessed with the internal, personal, and situational attribution questionnaire. Insight was assessed with both a clinician-administered and a self-administered measure. Results revealed that EB was negatively correlated with insight as assessed with the clinician-administered but not the self-administered measure of insight. (Contains 2 tables.)