Our aims were to (1) examine possible neuroanatomical abnormalities associated with the Disruptive Behavior Disorders (DBDs) as a group; and (2) assess neuroanatomical anomalies specific to each DBD. Cortical thickness analysis and voxel-based morphometry were analyzed in 47 eight-year-old children (22 DBDs and 25 healthy controls) from Magnetic Resonance Imaging (MRI) brain scans. DBD symptoms were assessed using the Dominic-R. In DBD subjects relative to controls, we found: (1) a decreased overall mean cortical thickness; (2) thinning of the cingulate, prefrontal and insular cortices; and (3) decreased gray matter density (GMd) in the same brain regions. We also found that scores on the Dominic-R were negatively correlated with GMd in the prefrontal and precuneus/superior temporal regions. There was a sub-diagnostic main effect for ADHD related to thinning in the cingulate, whereas conduct disorder showed thinning of the middle/medial frontal, and oppositional defiant disorder in the left rectal/orbitofrontal. Findings suggest that thinning and decreased GMd of the insula disorganizes prefrontal circuits, diminishing the inhibitory influence of the prefrontal cortex on anger, aggression, cruelty and impulsivity, and increasing a person's likelihood of aggressive behavior. These findings have implications for pathophysiologic models of the DBDs, their diagnostic classification system and for designing more effective intervention programs.