Burnout and reduced well-being are highly prevalent among Japanese medical students during clinical training. Scalable, evidence-based interventions are urgently needed. This protocol outlines a nationwide randomised controlled trial (RCT) to evaluate a self-guided, on-demand Acceptance and Commitment Training (ACT) programme for reducing burnout and improving well-being during clinical clerkships.

This two-arm, open-label, parallel-group RCT will recruit 128 Japanese medical students in clinical clerkships, randomised to on-demand ACT or no-intervention control. The ACT intervention comprises three self-guided online modules at weeks 0, 2 and 4, plus a 30 min online booster (weeks 8–10). Self-reported outcomes are measured at baseline, mid-intervention, postintervention and at 14-week primary endpoint (week 14). The primary outcome is medical student burnout (Oldenburg Burnout Inventory for Medical Students). Secondary outcomes include well-being (Mental Health Continuum-Short Form), professional burnout (Maslach Burnout Inventory–Human Service Survey), psychological flexibility (Work-related Acceptance and Action Questionnaire, Valuing Questionnaire), depressive symptoms (Patient Health Questionnaire-9), mental illness stigma (Mental Illness: Clinicians’ Attitudes Scale version 4), ACT process knowledge (ACT Check, applied section); adverse events and serious adverse events and adherence (platform completion and engagement metrics), all assessed at prespecified time points. Data will be analysed using mixed-effects models for repeated measures on an intention-to-treat basis.

This protocol was approved by the Nagoya City University Clinical Research Review Board (No. 70-22-0022) and registered with the Japan Registry of Clinical Trials (jRCT1042250024). Results will be disseminated via publications and conference presentations.

jRCT1042250024.