Children with autism spectrum disorder (ASD) are at greater risk for experiencing high levels of anxiety symptoms. Recent evidence suggests Cognitive behavioral therapy (CBT) may also be effective for anxiety reduction in some presentations of ASD. This meta-analysis evaluated twenty-three studies. Results yielded a moderate effect size (g = -0.66) for the reduction of anxiety symptoms. Moderators indicated larger effects for studies were achieved with parental involvement (g = -0.85, p < 0.05) than with child-only treatments (g = -0.34, p < 0.05). Short-term interventions generated a smaller effect (g = -0.37 p < 0.05) than either standard-term (g = -1.02, p < 0.05) or long-term interventions (g = -0.69, p < 0.05). Implications for children with ASD are discussed.