Background Social anxiety is a heightened fear and discomfort in social situations which can be experienced in varying degrees of severity. Cases of elevated distress and impaired functioning and quality of life can lead to a clinical diagnosis of social anxiety disorder. Altering cognitive biases associated with social anxiety has been suggested as potentially beneficial; however, little is known about the comparative effectiveness of such interventions. The aim of this living systematic review is to examine the efficacy of cognitive bias modification for reducing social anxiety, including in people who have not been diagnosed with the disorder. Methods We will search multiple electronic databases for randomised controlled trials evaluating the efficacy of cognitive bias modification for people diagnosed with social anxiety and people exposed to a simulated social stressor. The primary outcome will be change in social anxiety related symptoms; secondary outcomes will be changes in social functioning and quality of life and adverse events. Study selection, data extraction and risk of bias assessment will be done by at least two reviewers using pre-defined tools. We will synthesise data from people with social anxiety diagnosis and those subjected to a simulated social stressor separately using random effects meta-analyses. Heterogeneity will be evaluated by investigating characteristics of included studies. We will appraise the strength of the evidence for each outcome by reviewing the overall association, internal and external validity, and reporting biases. Where data allows, we will triangulate the evidence from both sources with a multidisciplinary group of experts. The review will begin in living mode and the database search will be rerun every three months to identify and integrate potential new evidence. We will co-produce this review with members of a global lived experience advisory board. This protocol was registered with PROSPERO (CRD42024601380) on 15.10.2024.