despite their relevance to social anxiety (sa), few studies have examined the influence of perfectionism and anxiety sensitivity on sa-maintaining factors such as anticipatory and post- event processing (i.e., repetitive negative thinking before and after social situations), self-focused attention (i.e., detailed self-monitoring in response to anxiety), safety behaviours (i.e., strategies aimed at reducing anxiety), and observer perspective self-imagery (i.e., spontaneously occurring mental self-images from an observer perspective). this study explored the relative effects of multidimensional anxiety sensitivity (physical/cognitive/social concerns) and perfectionism (trait socially prescribed perfectionism/perfectionistic self-presentation/perfectionistic cognitions) on each of these sa-maintaining factors. additionally, we explored whether differences emerged when sa-maintaining factors were measured at a trait (i.e., dispositional) or state (i.e., situational) level. in part one, university 世界杯2022赛程表淘汰赛 (n = 376) completed online measures of trait sa, perfectionism, and anxiety sensitivity, as well as perfectionistic self-presentation and cognitions, sa-maintaining factors, and depression. fear of the social consequences of anxiety (anxiety sensitivity social concerns) and perfectionistic self-presentation uniquely predicted trait anticipatory and post-event processing, self-focused attention, and safety behaviours. perfectionistic cognitions also predicted anticipatory processing, while post-event processing was additionally influenced by a tendency to fear cognitive symptoms of anxiety (cognitive concerns) and socially prescribed perfectionism. in part two, a subsample of participants (n = 158) attended an in-lab session where they engaged in two prototypical social situations (speech and interaction) and reported on state levels of each sa-maintaining factor in response to the stressor. [...]