["Psychology in the Schools, EarlyView. ", "\nABSTRACT\nTeachers with high levels of burnout and reduced levels of wellbeing are twice as likely to leave the teaching profession. For those that stay, it can result in strained relationships with their pupils and a difficulty to effectively manage classroom behavior. This study focused on the emotional strain felt by teachers during periods of educational disruption and how his varied according to school size, school‐level disadvantage and levels of pupil‐reported bullying and victimization. Data were collected from 11,111 primary school pupils and their 748 teachers in 2020 before the pandemic lockdowns, and in the summer of 2021 when schools had re‐opened. Teacher wellbeing and burnout levels (exhaustion, cynicism and professional efficacy) were collected. Teachers reported higher levels of burnout and reduced levels of wellbeing after the school disruption, and teachers of classrooms with the highest proportion of pupil bullying perpetration were found to have the lowest levels of teaching professional efficacy. This study identifies that suitable support needs to be in place for teachers during or following an educational disruption, especially for teachers struggling with challenging classroom dynamics, such as bullying. We suggest that a whole‐school support network and program that equips schools to attend to the wellbeing needs for teaching staff could be developed."]