The current study investigated whether a multidimensional model could underlie impulsivity and its associations with various disorders in a forensic sample. Data were available from self-report and behavioral impulsivity instruments of 87 forensic patients. Principal component analysis (PCA) was used to derive a dimensional impulsivity model, and the relationship between and possible predictive validity of impulsivity dimensions for psychopathology was investigated using product moment correlations and regression analysis. A 3-dimensional model of impulsivity was derived, with factors labeled impulsive decision making, sensation seeking, and response inhibition. Impulsive decision making was a predictor for a history of drug dependence, the impulsive lifestyle facet of psychopathy, and antisocial personality disorder. Sensation seeking was not related to any psychopathology. Inadequate response inhibition was a predictor for drug dependence, psychopathy, and antisocial personality disorder. Given the importance of the concept of impulsivity with regard to forensic risk assessment, the current results replicated earlier impulsivity models and imply that impulsivity is a crucial target for diagnosis and interventions and underlines the importance to consider impulsivity as a multidimensional construct.