Anxiety is a common problem in school-aged children with autism spectrum disorder (ASD). Cognitive behavioral therapy (CBT) and other psychosocial interventions have been developed as alternatives to pharmacological intervention to treat anxiety symptoms in students with ASD without co-occurring intellectual disability. This present synthesis of evidence is a systematic review and meta-analysis examining the efficacy of interventions for reducing anxiety among school-aged children with ASD. This review aims to address the question of what the relative effectiveness of interventions is for managing anxiety of school-aged children with ASD in school, family, and clinical settings. Twenty-four studies, involving 931 school-aged children with ASD (without co-occurring intellectual disability) and clinical anxiety, are summarized in this review. Overall, the effects of interventions on anxiety show a statistically significant moderate to high effect, compared to waitlist and treatment-as-usual control conditions at posttreatment.