Four groups of student hallmates provided similarity ratings of each other, and they rated each other on various characteristics. Group level multidimensional scaling analyses suggested that there was no consensual social structure in any of the four groups. In contrast, individual level analyses found that individuals had coherent perceptions of the social structures of their groups, although no two members of any group perceived the social structures of their group similarly. Nonetheless, there was considerable similarity among people in the dimensions underlying their perceived structures. Conventionality, friendliness, influence, and interpersonal openness served as organizing dimensions for the majority of participants, and sense of humor, how hard it was to get along with people, introversion, interesting, and academic orientation, were important bases for about a third of the participants.