Extraversion is a fascinating personality dimension that consists of two major components, agentic extraversion and affiliative extraversion. Agentic extraversion involves incentive motivation and is expressed as a tendency toward assertiveness, persistence, and achievement. Affiliative extraversion involves the positive emotion of social warmth and is expressed as a tendency toward amicability, gregariousness, and affection. Here we investigate the neuroanatomical correlates of the personality traits of agentic extraversion and affiliative extraversion using the Multidimensional Personality Questionnaire brief form (MPQ-BF), structural magnetic resonance imaging (MRI), and voxel-based morphometry (VBM) methods in a sample of 83 healthy adult volunteers. We found that trait agentic extraversion and trait affiliative extraversion were each positively associated with the volume of the medial orbitofrontal cortex bilaterally (t’s ≥ 2.03; r’s ≥ .23, p’s <0.05). Agentic extraversion was specifically and positively related to the volume of the left parahippocampal gyrus (t = 4.08, r = .21, p < 0.05), left cingulate gyrus (t = 4.75, r = .28, p < 0.05), left caudate (t = 4.29, r = .24, p < 0.05), and left precentral gyrus (t = 4.00, r = .18, p < 0.05) in males and females, and the volume of the right nucleus accumbens in males (t = 2.92, r = .20, p < 0.05). Trait affiliative extraversion was not found to be associated with additional regions beyond the medial orbitofrontal cortex. The findings provide the first evidence of a neuroanatomical dissociation between the personality traits of agentic extraversion and affiliative extraversion in healthy adults.