Therapeutic horseback riding (THR) is frequently sought out as an alternative treatment to address the behavioral disturbances that often impair the quality of daily life for individuals with an autism spectrum disorder (ASD); however, there are only a few published evidence-based THR studies to guide clinicians and consumers. This study aims to expand on a pilot study that found significant improvement in self-regulation, communication, and motor skills for ASD participants involved in 10 weeks of therapeutic horseback riding compared to a 10 week waitlist control group. This study will attempt to replicate these pilot findings as well as the social motivation findings from a recent THR study by examining a larger sample and using a randomized control design. Furthermore, it will test whether the human-animal interaction is necessary for the significant changes observed in the pilot study. This question will be examined by comparing ASD participants' involvement in 10 hours of weekly therapeutic horseback riding (n = 40) to a barn activity control group (n = 40) that targets the same therapeutic goals and controls for time and attention effects, but has no human-animal interaction. Pre-and post-intervention evaluations will assess participants' self-regulation, communication, socialization, and motor functioning. A secondary aim of the study is to determine if improvements made as a result of involvement in 10 weeks of THR persist approximately six months beyond the THR intervention. Determining if and how the human-animal interaction via THR is helpful to individuals with an ASD has far-reaching implications for the quality of life in this ASD population and their caregivers.