Personality disorder (PD) diagnosis is currently in flux, with the latest edition of the International Classification of Diseases proposing to overhaul PD classification. The stigma purportedly attached to PD labels is a common concern in debates about PD diagnosis. However, there is a paucity of data on the general public's attitudes to PD diagnoses. The current study used an experimental vignette method to explore (a) whether attitudes to a person displaying undesirable behavior are affected by disclosing a PD diagnosis, and (b) whether the different variants of PD diagnoses present in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and International Classification of Diseases elicit different social responses. Participants (n = 328) were recruited via an online platform and randomly assigned to read one of six vignettes. Vignettes described a person displaying socially undesirable behaviors, whose diagnosis was either withheld or defined as Borderline, Antisocial, Mild, Moderate, or Severe PD. Participants then completed a battery of measures assessing their attitudes to the vignette character. Relative to groups who were told of a PD diagnosis, diagnostically unaware participants were less likely to see the person's problems as biologically caused, expected the problems would be shorter in duration, and attributed the character more a greater degree of personal control over their conduct. Withholding a diagnosis also resulted in greater anger and social distance and less positive affect and pity. Between the conditions in which different diagnostic classifications were stated, the specific terminology used had minimal effect. Results suggest that disclosing a PD diagnosis may ameliorate negative responses to undesirable behavior, irrespective of the particular diagnostic terminology used. (PsycInfo Database Record (c) 2021 APA, all rights reserved).