This study aimed to examine the effect of emotion recognition training on social anxiety symptoms among adolescents, aged 15–18 years. The study included a screening session, which identified participants who scored above a cut-off on a self-report measure of social anxiety for enrolment into a randomized controlled trial (Clinical Trials ID: NCT02550379). Participants were randomized to an intervention condition designed to increase the perception of happiness over disgust in ambiguous facial expressions or a sham intervention control condition, and completed self-report measures of social anxiety, fear of negative evaluation, anxiety-related disorders, and depressive symptoms. The intervention group demonstrated a strong shift in the balance point at which they perceived happiness over disgust in ambiguous facial expressions. This increase in positive perception was not associated with any changes in the primary outcome of social anxiety; however, some evidence of improvement in symptomatology was observed on one of a number of secondary outcomes. Those in the intervention group had lower depression symptoms at 2-week follow-up, compared to those in the control group who received the sham intervention training. Potential reasons for why the shift in balance point measurement was not associated with a concurrent shift in symptoms of social anxiety are discussed.