This study, grounded in situated learning and communities of practice, examines the social dimensions of mathematics teacher identity, focusing on engagement, alignment, and imagination as defined by Wenger (1998, 2010). These aspects of belonging influence how teachers navigate their roles, interactions, and participation within school communities. The research centres on Mr. Khan, a Grade 10 mathematics teacher with 26 years of experience, whose identity reflects a blend of participation and marginalization. Data were collected through classroom observations, field notes, and three semi-structured interviews: an identity interview, a teacher-knowledge interview, and a reflection interview. These were analyzed to explore how his identity evolved within his professional context. Mr. Khan’s teaching practices were influenced by his personal experiences, beliefs, and relationships with learners. He maintained a structured, traditional classroom, utilising group leaders to encourage peer learning. However, his identity development revealed tensions between his pedagogical choices and interactions with colleagues and the broader school community. His engagement with students and alignment with his role as a teacher were informed by his reflections on his career path, shaped by external pressures and evolving aspirations. The study demonstrates that teacher identity is fluid, negotiated within both professional and personal contexts. Wenger’s framework helps explain Mr. Khan’s struggle to balance his passion for teaching with feelings of alienation, limited agency, and marginalization within the school environment. His ability to envision alternative professional paths underscores the complex dynamics of belonging and identity in teaching. This research contributes to the understanding of mathematics teacher identity by highlighting how teachers manage the tension between personal agency and professional expectations. It emphasizes the need for supportive environments that recognize the complexities of teacher identity and promote meaningful participation and inclusion.

Keywords: Mathematics teacher identity, situated learning, communities of practice, teacher agency, marginalization.