Cognitive biases play a crucial role in the development and maintenance of social anxiety. Previous research suggests that individuals with elevated social anxiety are more likely to interpret ambiguous social situations as threatening. However, few studies have experimentally manipulated interpretation bias to examine its influence on attention bias and anxiety responses. This study aimed to investigate whether modifying interpretation bias influences attention bias and state anxiety in the presence of a social stressor. Seventy university students with high social anxiety scores and a fear of public speaking participated in a single-session interpretation bias modification training in a laboratory setting. Participants were randomly assigned to either an interpretation-training or a control condition. Before the training, all participants were instructed to deliver an impromptu speech to induce state anxiety. In the interpretation-training condition, participants received positive feedback for benign interpretations and negative feedback for threat interpretations. In the control condition, positive and negative feedback were presented equally. Following the training, participants completed a battery of questionnaires and tasks assessing interpretation and attention biases. Compared to the control group, participants in the training condition showed increased endorsement and decreased rejection of benign interpretations, as well as faster rejection of threat-related word-sentence pairs from pre- to post-training. These effects generalized to a separate measure of interpretation bias. Serial mediation analyses indicated that interpretation bias mediated the relationship between group condition and state anxiety; however, changes in interpretation bias did not generalize to attention bias. The findings suggest that interpretation bias modification can effectively promote benign interpretations and reduce threat-related appraisals in socially anxious individuals. By decreasing socially threatening interpretations, such interventions may serve as preventive methods for reducing anxiety-related stress responses.