This study investigates the influence of interpersonal communication and intergroup identification on members' evaluations of computer-mediated groups. Participants (N= 256) in 64 four-person groups interacted through synchronous computer chat. Subgroup assignments to minimal groups instilled significantly greater in-group versus out-group identification. One member in each group was instructed to exhibit interpersonally likable or dislikable behavior. Analysis revealed that confederates acting likably were more attractive than those acting dislikably regardless of their in-group or out-group status. Further results indicated that interpersonal behavior interacted with subgroup membership on identification shifts following online discussions. Interpersonal dynamics generally provided stronger effects on members in virtual groups than did intergroup dynamics, in contrast to predictions from previous applications of social identification to computer-mediated communication.