Abstract
This study examines the role of structured mentorship in promoting sustainable professional development (SPD) among English language teachers in low-resource contexts. Using a sequential explanatory mixed-methods design, quantitative data from 120 teachers were analyzed through partial least squares structural equation modeling (PLS-SEM), followed by qualitative insights from 50 participants collected through interviews, reflective journals, and mentoring artifacts. Findings highlight three interdependent pathways through which mentorship enhances teacher growth: instructional reconstruction, reflective empowerment, and socio-emotional scaffolding. These pathways are shaped by leadership practices, institutional culture, and resource constraints, with monitoring emerging as the most supportive practice when implemented formatively. Digital and hybrid mentoring models, which integrate peer collaboration, expert guidance, and online platforms, proved especially valuable in sustaining engagement and fostering pedagogical innovation under challenging conditions. The study contributes a multi-level conceptual framework that positions mentorship not merely as skill transfer but as a relational, identity-forming, and resilience-building process embedded in specific socio-cultural contexts. By aligning with Sustainable Development Goal 4 (Quality Education), this work underscores mentorship’s systemic role in strengthening teacher capacity in under-resourced settings. Future directions are identified in the use of digital technologies and emerging AI tools to extend mentorship access, personalize support, and enhance long-term sustainability. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-025-29242-5.