Individual randomized controlled trials (RCTs) of habit reversal training and a Comprehensive Behavioral Intervention for Tics (collectively referred to as behavior therapy, BT) have demonstrated efficacy in reducing tic severity for individuals with Tourette Syndrome and Chronic Tic Disorders (collectively referred to as TS), with no examination of treatment moderators. The present meta-analysis synthesized the treatment effect sizes (ES) of BT relative to comparison conditions, and examined moderators of treatment. A comprehensive literature search identified eight RCTs that met inclusion criteria, and produced a total sample of 438 participants. A random effects meta-analysis found a medium to large ES for BT relative to comparison conditions. Participant mean age, average number of therapy sessions, and the percentage of participants with co-occurring attention deficit hyperactivity disorder (ADHD) were found to moderate treatment effects. Participants receiving BT were more likely to exhibit a treatment response compared to control interventions, and identified a number needed to treat (NNT) of three. Sensitivity analyses failed to identify publication bias. Overall, BT trials yield medium to large effects for TS that are comparable to treatment effects identified by meta-analyses of antipsychotic medication RCTs. Larger treatment effects may be observed among BT trials with older participants, more therapeutic contact, and less co-occurring ADHD