AbstractThe General Theory of Crime proposes that crime is explained by the combination of situational opportunity and lack of self‐control. Impulsivity is one of the important components of self‐control. Because behavioral measures of impulsivity are becoming more commonly utilized to assess forensic populations, this manuscript provides an overview of three current behavioral measures. In doing so, an example of their application is provided using a group of individuals likely to come into contact with the legal system: adolescents with Conduct Disorder. Earlier age of onset of Conduct Disorder symptoms has been shown to be an important predictor of the persistence of poor outcomes into adulthood, including participation in criminal activities. This study found differential behavioral profiles across distinct measures of impulsivity by those with childhood‐ versus adolescent‐onset Conduct Disorder. Legal implications for defining behavioral deficits using behavioral measures of impulsivity and their current limitations are discussed. Copyright © 2008 John Wiley & Sons, Ltd.