Students with disabilities have been educated in the general education classroom since the 1990s. General education teachers are expected to provide instruction to students with disabilities while working alongside the special education teacher. Providing instruction to students with disabilities in general education classrooms without purposely creating shared expectations and building professional relationships has hurt all students school experience. Forming positive coteaching relationships takes time and requires planning to address challenges that may arise between co-teachers as well as providing instruction for all students in the class. This study uses Improvement Science to understand teachers' perceptions of co-teaching in inclusion classrooms and support them in understanding and applying co-teaching models. Three primary themes emerged: (a) the importance of planning for co-teaching, (b) the variation in instructional strategies employed in inclusion classrooms, and (c) the variation in student and teachers' perceptions of co-teaching. In this study, I also found that multiple strategies that teachers use for students with disabilities were also used for students without disabilities. [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.]