The purpose of the current investigation is to analyze extant research examining the impact of play therapy on the development of language skills in young children with autism spectrum disorder (ASD). As rates of ASD diagnoses continue to increase, families and educators are faced with making critical decisions regarding the selection and implementation of evidence-based practices or therapies, including play-based interventions, to support the developing child as early as 18 months of age. Research on rare diseases and low incidence disabilities are difficult and lack available evidence as the conditions and responses to interventions vary by person. The following study investigates whether play-based interventions should be considered as effective means of increasing language development in young children with ASD. In addition, this study was conducted to identify specific moderators or variables associated with the effectiveness of play-based interventions. In order to conduct the present investigation, a meta-analysis was conducted, based on a collection of available research. Using data extraction software, the researcher conducted statistical analyses, Tau-U and Hierarchical Linear Modeling (HLM), to measure effect sizes across the available data and further assess whether specific moderators play a role in the usefulness or success of play therapy to promote language development in young children with ASD. The results revealed that play-based interventions are considered an effective intervention to support language development in young children with ASD and identified frequency, duration, and type of play-based intervention as significant predictors of language development for young children with ASD who participate in play-based interventions. Such findings offer insights for educators, families, clinicians, and others who are make decisions regarding the recommendation, selection, and implementation of play-based therapy as an intervention to increase language development in young children with ASD. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]