This study aimed to investigate and improve collaborative educational leadership to eliminate the barriers created by the lack of inclusive pedagogy and the deficit approaches to instructing students with disabilities, which together limit access to the general education curriculum and classroom in school districts in the Northeast. The Cycle 1 research identified that the philosophy of inclusion, high-quality instructional practices, and access to resources impact the efficacy of co-teaching teams' development of multimodal instruction. The Cycle 1.5 research identified the role of the administrator of special education as vital to the success of implementing co-teaching. However, this role cannot function in isolation. Action steps were then designed, implemented, and evaluated for a second research cycle. During this participatory process, the administrators of special education and principals co-created administrative reflection tools to optimize collaboration with their in-district colleagues while strategizing to support their co-teaching teams, using co-teaching methodology. An evaluation of this action research study included focus groups, document analysis, transcriptions, analytic memos, and semi-structured interviews. The analysis of the data from all three cycles of collection demonstrated the importance of the co-administrators in supporting co-teachers in developing and implementing multimodal instruction to combat barriers against including students with disabilities in the general education classroom. Through examination of the instructional practices and relationships between co-teaching team members, the administrative strategies identified created opportunities to cultivate inclusive educational environments for students with disabilities. This study concluded that (a) school administrators need to develop a unified and unwavering philosophy of inclusion that is at the forefront of all communication and anchors all other actions, (b) educational leadership is vital to the success of co-teaching implementation, (c ) and the strategies implemented must be actioned with fidelity for the sustainability of co-teaching. [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.]