The role of interpersonal relationships in mediating the experience of crowding and loss of personal control was investigated in dormitory environments housing two or three students in bedroom units. A combination of survey, observational, and laboratory techniques was used to explore the formation of 2-person coalitions in tripled housing and subsequent problems created for the third, “left-out” roommate. Data strongly suggested that the aversiveness and loss of control previously associated with tripled residential settings may be more plausibly attributed to the inherent instability of 3-person groups and the loss of control associated with being excluded from group activities. In most of the tripled rooms studied, 2-person coalitions formed and most of the crowding and negative affect reported were expressed by the third roommate, who felt left out by the others. Residents of doubled rooms and members of coalitions in tripled rooms did not differ from one another on most dimensions.