This study investigates an initial attempt at utilising Greek Sign Language (GSL) for the benefit of both hearing and Deaf and Hard of Hearing (DHH) students, through the Co-Teaching method in secondary education. The research aims to explore the integration of GSL and Co-Teaching as an inclusive teaching approach within mainstream classrooms, contributing to the development of future educational environments that promote equity and inclusion.

The study addresses a gap in the literature and responds to the limitations of the current Greek educational system, where sign language is not incorporated into mainstream curricula. It focuses on the potential advantages, challenges, and prerequisites for implementing this method effectively. A qualitative research design was applied, utilising methodological triangulation to enhance validity and reliability. Data were collected through ten structured interviews with DHH students, special educators, and GSL interpreters; non-participant observation by the researcher; and a review of school documents from a High School of Patras, Greece, specifically in classrooms serving DHH students.

Particular attention was given to the literature course, which was identified as a suitable context for the application of this method due to its open-ended content and flexible structure. The findings, structured around three research questions and four thematic arguments, highlight the necessity of adopting this approach in schools that aim to eliminate social discrimination and promote both inclusion and the preservation of bilingualism and DHH culture.

The results suggest that Co-Teaching with GSL fosters both social inclusion and academic benefits for all students when implemented under specific conditions. These include reduced class size, sufficient educator training in both the Co-Teaching model and GSL, and institutional support. Moreover, the literature course appears especially conducive to this method due to its expressive and adaptable nature.

The study concludes by underlining the need for further research through pilot programs in secondary schools, as well as the organisation of educational seminars on GSL, Deaf culture, and inclusive teaching methods, aimed at both students and educators.

Keywords: Inclusive Education, GSL, Co-teaching, Teaching Method, Secondary Education, Literature Course.