Social anxiety is an experience of fear, apprehension or worry regarding social situations and being evaluated by others. People vary in how often they experience anxiety in this way or in which kinds of situations. Anxiety about public speaking, performance, or interviews is common. Social anxiety can be related to shyness. The experience is commonly described as having physiological components (e.g. sweating, blushing), cognitive/perceptual components (e.g. belief that one may be judged negatively; looking for signs of disapproval) and behavioral components (e.g. avoiding a situation).

Social anxiety disorder, also known as social phobia, is a diagnosis within psychiatry and other mental health professions referring to excessive long-lasting social anxiety causing relatively extreme distress and impaired ability to function in at least some areas of daily life. The diagnosis can be of a 'specific' disorder (when only some particular situations are feared) or a generalized disorder. Generalised social anxiety disorder typically involves a persistent, intense, and chronic fear of being judged by others and of potentially being embarrassed or humiliated by their own actions. These fears can be triggered by perceived or actual scrutiny by others. While the fear of social interaction may be recognised by the person as excessive or unreasonable, considerable difficulty can be encountered overcoming it. Approximately 13.3% of the general population may meet criteria for social anxiety disorder at some point in their lifetime, according to the highest survey estimate, with the male to female ratio being 1:1.5 respectively.

Physical symptoms often accompanying social anxiety disorder include excessive blushing, sweating (hyperhidrosis), trembling, nausea, and stammering. Panic attacks may also occur under intense fear and discomfort. An early diagnosis may help in minimizing the symptoms and the development of additional problems such as depression. Some sufferers may use alcohol or drugs to reduce fears and inhibitions at social events.

A person with the disorder may be treated with psychotherapy, medication, or both. Research has shown cognitive behavior therapy, whether individually or in a group, to be effective in treating social phobia. The cognitive and behavioral components seek to change thinking patterns and physical reactions to anxious situations. Prescribed medication includes a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs). Attention given to social anxiety disorder has significantly increased since 1999 with the approval and marketing of drugs for its treatment.