Introduction: Autism spectrum disorder (ASD) is a prevalent neurodevelopmental condition with significant impacts, and the benefits of animal-assisted therapy (AAT) in this population are unclear. This review aims to inform clinical decision-making and guide future research in AAT for children with ASD. Methods: We conducted a comprehensive search across PubMed, Cochrane Library, Embase, and ScienceDirect of randomized controlled trials of AAT in children with ASD, published until July 2023. Other inclusion criteria involved English-language articles and full-text availability. The selection process adhered to PRISMA 2020 guidelines, and the Cochrane Bias Assessment Tool was used for quality appraisal. Results: 45 studies were retrieved; six were included after removing duplicates and applying criteria. These studies included 300 children with ASD who received different AATs as an add-on therapy with a follow-up range of 7 to 16 weeks. Additional outcomes were measured with multiple scales. Overall, studies described that AAT has various benefits in this population, including improving cognitive, communication, and social skills, increasing adaptive behaviors, and reducing irritability and hyperactivity compared to control groups that did not receive AAT. The risk of bias measured with the Cochrane Bias Assessment Tool showed varied methodological quality among studies. Conclusion: Whether involving dogs or horses, AAT can improve overall quality of life, reduce autism-related behaviors, enhance communication and cognitive skills, promote social development, and mitigate anxiety. While encouraging, further research is imperative to strengthen the evidence base and assess the long-term effects of AAT in this population.