Teacher wellbeing is an important prerequisite for promoting student wellbeing, yet there is limited research exploring the potentiality of classroom management training for enhancing teacher psychological outcomes. This study used a pragmatic, pre-experimental design to evaluate a psychologist-led 6-month Incredible Years Teacher Classroom Management programme with 368 Irish primary teachers using well-validated measures of self-efficacy ("Teacher Sense of Efficacy Scale-Long Version"), wellbeing ("Everyday Feelings Questionnaire") and burnout ("Maslach Burnout Inventory Educators Survey"). Mixed ANOVAs revealed significant improvements in wellbeing (p < 0.001, n[subscript p][superscript 2] = 0.08), emotional exhaustion (p = 0.01, n[subscript p][superscript 2] = 0.02), personal accomplishment (p < 0.001, n[subscript p][superscript 2] = 0.07), and self-efficacy (p < 0.001, n[subscript p][superscript 2] = 0.30) among participants. Whilst results must be interpreted cautiously, this study is positioned as being suggestive of psychological benefits for teachers accruing from evidence-based classroom management training.