Social rejection is a powerful negative emotional experience, yet rejected people often appear stoic and unmoved. That is, their macroexpressions of emotion are not accurate reflections of their emotional states. Yet, there is reason to believe that rejected people exhibit involuntary microexpressions of negative emotion. We contrasted people's macroexpressions of emotion with their microexpressions subsequent to an acceptance or rejection experience. Observers coded microexpressions after being trained with the Micro Expression Training Tool (METT). Rejected participants expressed more sad and angry microexpressions than did accepted participants. This research demonstrates that socially rejected people display negative microexpressions that are detectable by observers trained in the METT.