The purpose of this study was to reveal the effects of the disruption to face-to-face education during the pandemic on the classroom environment upon return to the classroom. The participants of this case study were 16 teachers working in Turkey. The data were collected through semi-structured interviews and their contents were analysed. The study revealed that there were cognitive changes, motivation and concentration problems, social changes, discipline problems, and psychomotor changes observed in students' behaviours after the transition to face-to-face education. The sources of the behavioural changes were the family, the Ministry of National Education, being away from school, and use of technology. The strategies used by the teachers in terms of classroom management while managing the process after the transition to face-to-face education were management of teaching, behaviour management, management of relationships, and management of the physical environment.