We examined the role of baseline patient characteristics as predictors of outcome (end‐state functioning, response and remission) and attrition for cognitive therapy (CT) in social anxiety disorder (SAD). Beyond socio‐demographic and clinical variables such as symptom severity and comorbidity status, previously neglected patient characteristics (e.g., personality, self‐esteem, shame, interpersonal problems and attachment style) were analysed. Method Data came from the CT arm of a multicentre RCT with n = 244 patients having DSM‐IV SAD. CT was conducted according to the manual by Clark and Wells. Severity of SAD was assessed at baseline and end of treatment with the Liebowitz Social Anxiety Scale (LSAS). Multiple linear regression analyses and logistic regression analyses were applied. Results Up to 37% of the post‐treatment variance (LSAS) could be explained by all pre‐treatment variables combined. Symptom severity (baseline LSAS) was consistently negatively associated with end‐state functioning and remission, but not with response. Number of comorbid diagnoses was negatively associated with end‐state functioning and response, but not with remission. Self‐esteem was positively associated with higher end‐state functioning and more shame with better response. Attrition could not be significantly predicted. Conclusions The results indicate that the initial probability for treatment success mainly depends on severity of disorder and comorbid conditions while other psychological variables are of minor importance, at least on a nomothetic level. This stands in contrast with efforts to arrive at an empirical‐based foundation for differential indication and argues to search for more potent moderators of therapeutic change rather on the process level. Key Practitioner Message Personality, self‐esteem, shame, attachment style and interpersonal problems do not or only marginally moderate the effects of interventions in CT of social phobia.Symptom severity and comorbid diagnoses might affect treatment outcome negatively.Beyond these two factors, most patients share a similar likelihood of treatment success when treated according to the manual by Clark and Wells. Copyright © 2014 John Wiley & Sons, Ltd.