This study drew on a community of practice (CoP) perspective and examined the role of religious ideology in 10 Iranian English language teachers' identity construction. The study was situated within a narrative inquiry methodology. Data were collected from semi-structured interviews and narrative frames to capture how Islamic principles contribute to the teachers' professional practice and identity construction. Our findings revealed that religious ideology shaped the teachers' identity construction across teaching materials, institutional relationships, and tensions between the normative and personalized ideologies of the teachers. We show how religious ideology, as extended to the context of the school CoP, functions as a source of tensions for the teachers by promoting materials that clash with their internal feelings and creates detachment in their institutional relationships. Moreover, the religious ideology served as a source of marginalization, detachment from the dominant religious principles, and attachment to personal values as practical alternatives facilitating teachers' membership. We further provide implications for running professional development courses that enhance teachers' awareness of the role of religious ideology in their professional practice.