BackgroundEmbarrassment is a self-conscious emotion with important social functions, but it is not well understood. The perception of bystanders is considered a precondition for embarrassment, which makes it unique from other self-conscious emotions. Studies have shown that socially close bystanders can reduce individuals’ embarrassment. However, whether and how the embarrassment of individuals varies with the changes in social distance between them and their bystanders remained unclear, which indicates the key characteristics of embarrassment.MethodsThe current research consists of two studies. Study 1 tested whether participants’ embarrassment systematically varied with social distance by setting up three levels of social distance: close friends (i.e., short), casual friends (i.e., medium), and strangers (i.e., long), based on 159 participants. With two full mediation models, study 2 investigated whether and how the fear of negative evaluation and state attachment security mediated the influence of social distance on embarrassment based on 155 participants.ConclusionsThe current findings revealed that the social distance between bystanders and protagonists systematically influenced the embarrassment of protagonists and this effect occurred via two parallel pathways, i.e., by increasing the fear of negative evaluation and by reducing state attachment security. The findings not only showed the unique role of bystander characteristics on embarrassment, but also two cognitive processes behind this unique self-conscious emotion: fearing negative evaluation and seeking attachment for security.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40359-023-01201-7.