["Journal of Computer Assisted Learning, Volume 42, Issue 3, June 2026. ", "\nABSTRACT\n\nBackground\nInformal Digital Learning of English (IDLE) has become increasingly prevalent among EFL learners, yet its integration into formal instruction remains uneven.\n\n\nObjective\nGuided by an ecological framework, this study examines the barriers that Thai EFL teachers encounter when attempting to integrate IDLE into secondary school classrooms.\n\n\nMethods\nQualitative data (929 coded responses) were collected from 350 secondary school EFL teachers across 55 provinces, representing all six regions of Thailand.\n\n\nResults\nBarriers were most commonly reported at the exosystem level (40%), including limited infrastructure, exam‐oriented curricula, and heavy workloads. These constraints were accompanied by microsystem challenges (22%), such as variation in students' proficiency levels and concerns about classroom distraction, as well as mesosystem barriers (14%), including unequal access to technology at home and parental resistance. Individual‐level factors (13%), such as limited confidence and reservations about digital learning, were also reported, alongside macrosystem influences (12%) related to traditional teaching norms. Reported percentages reflect descriptive prevalence rather than barrier severity or importance.\n\n\nConclusions\nThe findings suggest that teachers' decisions regarding IDLE integration are shaped largely by systemic and contextual conditions. Meaningful and sustainable integration may therefore depend on coordinated efforts that address institutional, curricular, and societal factors alongside targeted teacher support.\n\n"]