Autism spectrum disorder is the fastest growing developmental disability in the United States. The significant increase of an autism diagnosis among children requires further evaluation of instructional approaches that are designed to meet the unique needs of students with ASD. Although research has indicated that academic performance plays a crucial role in the quality of life of students with ASD, the data on academic performance of these subgroup of students, particularly in the key domains of math and reading, report generally poor academic outcomes. This study examined the association between the PBL instructional approach and academic outcomes in reading and math among students with ASD in K-12 public schools, as well as the extent to which PBL instructional approaches are associated with levels of motivation for learning among this population. The researcher employed a nonexperimental, quantitative research design. The sample for this study was derived from the Special Education Elementary Longitudinal Study (SEELS) data set and included students whose primary disability was coded as autism and who received English language and math instruction in inclusive settings. Given these parameters, the total sample included 237 students. The results of the study revealed statistically significant and positive results with variation in levels of the association between the PBL and specific academic skills. The study results also indicated no association between the PBL approach and motivation for learning. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]