||This is a comprehensive study to determine the most appropriate classroom structure to increase academic growth for students with Autism performing two years or more behind grade level. Using experimental design, two classrooms were compared using multiple assessment tools and classroom based observations to identify the impact class size, student to teacher ratio, and environmental factors have on student performance. A group of twenty students pmiicipated in the study and academic growth was monitored over the course of one school year. For language mis and mathematics, ten students received academic suppmi in a small classroom setting of ten students. The other ten students were placed in a general classroom with seven additional peers for a class size of seventeen students. Through this study, it was found that class size and student to teacher ratio impacted the amount of time each classroom spent on standards based instruction and IEP goals. This directly impacted student results on standards based assessments and progress towards mastering IEP goals. Over the course of a year, students in the small classroom setting made similar or more growth than students in the larger classroom setting; justifying the need to keep this unique classroom structure to benefit academic growth for students performing significantly below grade level.