<![CDATA[This study investigates the institutionalization of Ecological English Language Teaching (Eco-ELT) within an Indonesian boarding school context. Moving beyond viewing Eco-ELT as a pedagogical innovation, the study conceptualizes it as an institutional process shaped by leadership, organizational culture, and structural mechanisms. Employing a qualitative case study design, data were collected through semi-structured interviews with the principal and English teachers, classroom observations, and document analysis of school policies and sustainability programs. The data were analyzed thematically to identify patterns related to institutional framing, pedagogical enactment, and sustainability challenges. The findings reveal that Eco-ELT is legitimized through alignment with the school’s ideological vision of character formation and sustainability, and embedded within what the institution terms a “life curriculum.” Leadership plays a central role in articulating moral direction, while teachers function as mediating agents who translate institutional discourse into classroom practice. Structural supports, including language policies and environmental routines, reinforce the continuity of sustainability integration beyond formal instruction. However, the institutionalization process remains partially reliant on normative leadership and organizational culture, with limited formal codification in written policy frameworks. This study contributes to the emerging discourse on Eco-ELT by reframing sustainability-oriented language education as an institutional project rather than merely a curricular adaptation. The findings highlight the importance of ideological coherence, distributed leadership, and structural alignment in sustaining environmental integration within English language teaching.]]>
