["Psychophysiology, Volume 63, Issue 5, May 2026. ", "\nABSTRACT\nSocial anxiety is marked by persistent fear responses to social cues, often maintained in the absence of repeated aversive social experiences. One potential mechanism underlying this persistence is the recurrent generation of negative social imagery, which may function as an internal source of threat. The present study investigated whether fear toward neutral social stimuli can be acquired through imagined fear‐relevant social scenarios alone, and whether this process is heightened in individuals with elevated social anxiety. Using an imagery‐based differential conditioning paradigm, neutral facial expressions were paired with fear‐relevant social imagery, neutral imagery, or no imagery in individuals with high and low social anxiety. During acquisition, faces associated with fear imagery elicited more negative valence and higher arousal ratings than control stimuli, with these effects amplified in the high social anxiety group. Critically, only individuals with high social anxiety showed reliable differential autonomic responses, including increased skin conductance and heart rate acceleration, to the fear‐conditioned stimulus. During extinction, subjective fear and residual autonomic arousal persisted more strongly in the high social anxiety group, indicating impaired safety learning. Together, these findings provide psychophysiological evidence that internally generated threat representations can serve as effective unconditioned stimuli in fear learning, offering a mechanistic account of how negative social imagery contributes to the maintenance of social anxiety and highlighting the potential relevance of interventions targeting maladaptive social imagery.\n"]