Since the passage of PL 94-142, also known as the Education of All Handicapped Children Act, in 1975, special and general educators have been urged to work together to improve the education of children with disabilities through increased access to the general education curriculum. Over the years, the evolution of a collaborative approach to educating students with disabilities has resulted in the increased implementation of co-teaching as a service delivery model and a significant change in the role of the special educator. Co-teaching in inclusive education has been a topic of interest in academic research for more than 10 years and much of the existing research has been limited to exploring programmatic conditions for success or failure in collaboration and co-teaching and developing models of exemplary co-teaching practice. Despite the prevalence of these models and the research evaluating their efficacy, implementation of effective co-teaching in inclusive classrooms, particularly secondary level remains largely elusive. In this dissertation, I use critical theory and critical discourse analysis to theorize my research, as it allows for the examination of aspects of co-teaching that go unnoticed in traditional models and evaluations of co-teaching. In looking at co-teaching through this critical lens, I hope to begin a conversation about the importance of considering discursive aspects of teacher practice as a way to complement current models of practicing and evaluating co-teaching practice. In conducting a study of this nature, I sought to explore the discursive aspects of co-teaching that were immanent in the co-teachers' language and actions. Foucault's critical theories on discourse, power, dominance, and construction of the subject formed the theoretical basis for this study. Derived significantly from Foucault's conceptual work, Fairclough's Critical Discourse Analysis provided a complementary methodology to structure the majority of the analysis. Specifically, in the first phase of this study I studied their interactions at the local level of the classroom, the institutional level of the school district, and the societal level of governmental policy and legislation. The next phase of analysis extended on the first by exploring the patterns of dominance in the power relations between the two teachers. Finally, this study examined seven critical theoretical concepts that were prominent in the data-discourse, the institution, identity, inequality, ideology, agency, and historicity. Taken together, the three phases of analysis in this dissertation represent an in-depth examination of the co-teachers' professional relationship from a critical discursive perspective unlike any other study of co-teaching currently published. The participants in this qualitative case study included a New York State certified special education teacher and a New York State certified secondary math teacher who were assigned as co-teachers for a class of students with and without special education needs. Data for this study came from field notes and a series of videotaped interviews and observations involving the co-teachers, which were subsequently transcribed and coded for analysis. Extensive qualitative coding was used to locate patterns and themes in the data. The three phases of critical analysis presented in this study revealed that what superficially appeared to be a successful inclusive co-teaching relationship was in fact a marginalizing and exclusive arrangement for the teachers and students alike. However, this marginalization was not a conscious attempt to exclude Val or the students with IEPs from the educational benefits of Keith's general education math class. Rather, Val and Keith both resorted to traditional special education practices of segregation in an attempt to ensure their own survival as well as that of the students with IEPs in an educational environment that prioritized uniformity, high-stakes testing, and traditional conceptions of normalcy. [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.]