This study aims to investigate the preschool teachers' perceptions of behaviour and instructional management and their classroom practices with an explanatory sequential design, which is one of the mixed methods research. There were 319 participants in the quantitative stage and 29 participants in the qualitative stage of the research. Research data were collected through the Behaviour Management and Instructional Management scale and interview form. As a result of the research, preschool teachers' perceptions of behaviour and instructional management skills were high. There was a significant difference in teachers' behaviour and instructional management skills according to socioeconomic level and participation in in-service training. The teachers in the study carried out various activities related to determining and implementing classroom rules in behaviour management and determining and implementing teaching methods in instructional management. Teachers stated that when setting class rules, they preferred making joint decisions with children, providing information to children, identifying needs and using visuals. When implementing classroom rules, they preferred reminding children of the rules, using rewards and reinforcements, determination, providing information and using visuals. Teachers stated that they used cooperative learning, group work, individual learning, project and discussion methods in the classroom. Teachers took into account children's developmental characteristics and individual differences, ensured children's effective participation and included learning by doing and experiencing in their teaching methods practices. Teachers preferred practices were more consistent with interactionalist approaches in behaviour and instructional management.