Electroencephalogram-recorded epileptiform activity is common in children with autism spectrum disorder (ASD), even without clinical seizures. A systematic literature search identified 7 randomized, placebo-controlled trials of antiepileptic drugs (AEDs) in ASD (total n = 171), including three of valproate, and one each of lamotrigine, levetiracetam, and topiramate. Meta-analysis revealed no significant difference between medication and placebo in four studies targeting irritability/agitation and three studies investigating global improvement, although limitations include lack of power and different medications with diverse actions. Across all seven studies, there was no significant difference in discontinuation rate between two groups. AEDs do not appear to have a large effect size to treat behavioral symptoms in ASD, but further research is needed, particularly in the subgroup of patients with epileptiform abnormalities.