•Feeling authentic serves as a buffer against social rejection.•Feeling authentic results in lower feelings of rejections after social exclusion.•Experiencing authenticity leads people to appraise situations as less threatening.•These effects are not driven by affect or self-esteem but by authenticity.•Interventions that increase authenticity buffer against rejection. Social exclusion is a painful yet common experience in many people’s personal and professional lives. This research demonstrates that feeling authentic serves as a buffer against social rejection, leading people to experience less social pain. Across five studies, using different manipulations of authenticity, different paradigms to create social exclusion, and different measures of feeling rejected, we found that experiencing authenticity led participants to appraise situations as less threatening and to experience lower feelings of rejection from the social exclusion. We also found that perceived threat explains these effects. Our findings suggest that authenticity may be an underused resource for people who perceive themselves to be, or actually are, socially excluded or ostracized. This research has diverse and important implications: Interventions that increase authenticity could be used to reduce perceptions of threatening situations and the pain of impending exclusion episodes in situations ranging from adjustment to college to organizational orientation programs.