In school, shyness is associated with psychosocial difficulties and has negative impacts on children's academic performance and wellbeing. Even though there are different strategies and interventions to help children deal with shyness, there is currently no comprehensive systematic review of available interventions. This systematic review and meta-analysis aim to identify interventions for shy children and to evaluate the effectiveness in reducing psychosocial difficulties and other impacts. The methodology and reporting were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and checklist. A total of 4,864 studies were identified and 25 of these met the inclusion criteria. These studies employed interventions that were directed at school-aged children between six and twelve years of age and described both pre- and post-intervention measurement in target populations of at least five children. Most studies included an intervention undertaken in a school setting. The meta-analysis revealed interventions showing a large effect in reducing negative consequences of shyness, which is consistent with extant literature regarding shyness in school, suggesting school-age as an ideal developmental stage to target shyness. None of the interventions were delivered in a classroom setting, limiting the ability to make comparisons between in-class interventions and those delivered outside the classroom, but highlighting the effectiveness of interventions outside the classroom. The interventions were often conducted in group sessions, based at the school, and involved activities such as play, modelling and reinforcement and clinical methods such as social skills training, psychoeducation, and exposure. Traditionally, such methods have been confined to a clinic setting. The results of the current study show that, when such methods are used in a school-based setting and involve peers, the results can be effective in reducing negative effects of shyness. This is consistent with recommendations that interventions be age-appropriate, consider social development and utilise wide, school-based programs that address all students.