Question The aim of this systematic review is twofold: (1) to characterise the purpose and description of available social anxiety apps and (2) to review the evidence on the effectiveness of social anxiety apps. Study selection and analysis A search was conducted on three major mobile platforms: Apple iTunes, Google Play and Windows Store. Apps were included if they addressed social anxiety and used an English language interface. A systematic review of the literature from MEDLINE, EMBASE, PsycINFO, Cochrane, Scopus and Web of Science to identify evidence-based evaluations of social anxiety apps was also undertaken. Findings Of the 1154 apps identified, 38 apps met the inclusion criteria: iTunes (n=18), Google Play (n=16) and Windows Store (n=4). Over 60% of apps were exclusively focused on social anxiety, while the remainder targeted social anxiety and related conditions. Most developers did not provide information on their organisational affiliations or their content source. Most apps used multimedia while 17 apps used text only. Finally, although the systematic review of the literature identified 94 articles, none of which met inclusion criteria. conclusions Social anxiety apps have the potential to overcome barriers to accessing treatment; however, none of the apps identified have had studies on their effectiveness published. As the evidence base is lacking, it is therefore not currently possible to recommend their use.bAckground Social anxiety disorder is characterised by chronic fear and avoidance of social engagement, scrutiny by others and social withdrawal to avoid feelings of embarrassment and humiliation.1 It is highly prevalent and associated with major personal, social and economic burden.1-3 Although epidemiological studies on social anxiety have reported varying prevalence, one recent systematic review found that the global prevalence rate (after adjusting for methodological differences) is approximately 7.3%.