Functional neuroimaging has identified a neural system comprising posterior cingulate (pCC) and medial prefrontal (mPFC) cortices that appears to mediate self-referential thought. It is unclear whether the two components of this system mediate similar or different psychological processes, and how specific this system is for self relative to others. In an fMRI study, we compared brain responses for evaluation of character (e.g., honest) versus appearance (e.g., svelte) for oneself, one's mother (a close other), and President Bush (a distant other). There was a double dissociation between dorsal mPFC, which was more engaged for character than appearance judgments, and pCC, which was more engaged for appearance than character judgments. A ventral region of mPFC was engaged for judgments involving one's own character and appearance, and one's mother's character, but not her appearance. A follow-up behavioral study indicated that participants rate their own character and appearance, and their mother's character, but not her appearance, as important in their self-concept. This suggests that ventral mPFC activation reflects its role in processing information relevant to the self, but not limited to the self. Thus, specific neural systems mediate specific aspects of thinking about character and appearance in oneself and in others.