Misreading facial expressions as signals of social disapproval, such as anger and disgust, may maintain social anxiety. If so, manipulating face processing could be therapeutic. It remains unclear, however, whether socially anxious individuals are in fact more sensitive to disapproving emotions. We assessed decoding of, and cost attributions to, emotional expressions in high and low socially anxious females (n=102) using five emotions (anger, disgust, fear, happiness, and sadness) expressed at 15 intensities (9-65%), providing 75 stimuli (see Supplementary Material). The decoding task briefly presented the stimuli and participants identified the emotion. The cost attribution task asked individuals to rate each stimulus for how costly it would be for them to interact with the person. Random effects regression indicated that social anxiety was not associated with overall decoding accuracy but was associated with a response bias. High socially anxious individuals had a lower threshold for decoding emotions but also more frequently classified low intensity emotions incorrectly. These effects were not emotion-specific. Socially anxious individuals also attributed excessive social cost to expressions of negative valence. Our results provide a novel conceptual framework for understanding emotion decoding in social anxiety, indicating the importance of considering both accuracy and response bias.