The aim was to examine the impact of training on cognitive behavior therapy (CBT) formulation skills. Eighty-five clinicians were randomly assigned to two experimental conditions. The experimental manipulation was the timing of assessment of formulation skills, that is, either before or after participation in a training workshop. The preworkshop results suggest that there may be a gap between self-appraisal and actual performance on a formulation task. Formulation skills of clinicians were significantly better after they had undertaken the workshop compared with the preworkshop group, as measured by the Rating the Quality of Case Formulation for Obsessive–Compulsive Disorder (RQCFO). The current research suggests that time-limited, low-cost training can be effective in improving formulation competence for clinicians with previous knowledge.