Blushing is restricted to the facial area that is uncovered and in the center of social attention. Together with the observation that blushing typically occurs in interpersonal situations, it has been proposed that the blush might have acquired signaling properties with relevant social implications. Following such a functional perspective, this article evaluates the signal value and social effects of the blush. First, it is argued that the blush fulfils all criteria for being a reliable social signal. It seems impossible to fake or to suppress, and it seems to co-occur with a specific mental state: The acute awareness that one’s goal of esteem before others is at stake. Second, it is illustrated that the social effects of the blush may greatly vary as a function of context. In contexts that clearly imply some kind of misbehavior, the blush has face-saving properties. Yet, in many other contexts, such as merely being the center of attention or situations that are ambiguous with regard to the blushing actors’ antecedent behaviors, the blush may have undesirable effects. Third, it is illustrated that the signal value of the blush not only affects the observers but also the blushing actors. It is shown that the anticipated influence of one’s blushing on other people’s judgments may help explain why actors often consider blushing as a highly undesirable response, and why some people may even develop a phobic fear of blushing.