How do emotional expressions of group members shape conformity versus deviance in groups? We hypothesized that angry and happy responses to a group member's deviating opinion are interpreted as signals of imminent rejection versus acceptance. In 5 studies, the majority's expressions of anger led the deviant individual to feel rejected, whereas expressions of happiness made the deviant feel accepted. Because conformity can be seen as strategic behavior aimed at gaining (re)acceptance, the effects of emotional expressions on conformity should be moderated by social-contextual factors that determine the motivation to be accepted by the group and by the extent to which conformity is a means to this end. Accordingly, in Study 2, the availability of alternative groups determined whether a deviant conformed to the current group or abandoned the group after an angry reaction. In Study 3, anger and happiness were only associated with conformity pressure in situations that were perceived as cooperative (rather than competitive). Employing an interactive group task in Study 4, we showed that individuals who received an angry reaction contributed less in a cooperative group task than did those who received a neutral or happy reaction. Finally, in Study 5, peripheral group members conformed more after an angry reaction than after a happy reaction, but prototypical group members did not. Moreover, conformity was still manifest 3 weeks after the experiment, and this effect was mediated by feelings of rejection. We discuss implications of these findings for theorizing about social functions of emotions and the role of emotions in groups.