Co-teaching is a collaborative effort to support the learning of students identified with disabilities. Co-teaching is designed to provide students with disabilities an opportunity to enhance their academic achievement. Students with disabilities should be educated in the least restrictive environment for an equal and equitable opportunity to engage in an inclusive setting. This study set out to examine the effects of co-teaching on academic achievement in reading and math. The researcher analyzed quantitative reading and math data to examine the differences between students who did and did not participate in a co-taught instruction. Additionally, qualitative data was analyzed to provide an understanding of teachers' experiences. These findings may provide guidance to stakeholders when planning and implementing co-taught instruction. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]