Purpose: To examine the effects on anxiety of mindfulness-based interventions (MBIs) among youth with anxiety disorders. Method: Systematic review and meta-analytic procedures were employed to synthesize experimental and quasi-experimental studies authored between 1980 and 2015. Results: The search yielded five studies from five countries reporting results for a total of 188 youth between the ages of 5 and 18 (mean age 13.26) who met criteria for an anxiety disorder. Risk of bias varied across studies. Meta-analytic results suggest a moderate and significant effect (g = 0.62; 95% confidence interval = [0.20, 1.04], p = 0.004). Heterogeneity was moderate (I2= 47.22) and not statistically significant (Q = 7.58, df = 4, p = 0.11), thus moderator analyses were not warranted. Discussion: The findings of this review suggest that MBIs for the treatment of anxiety in youth with anxiety disorders are effective.