In the present investigation, teachers' self-reported knowledge and competency ratings for the evidence-based classroom management practices were analysed. Teachers also reflected on how they learned evidence-based classroom management practices. Results suggest that teachers working in schools that implement Positive Behavioural Interventions and Supports (PBIS) had significantly higher mean knowledge ratings in the area of posting, teaching, reviewing, monitoring and reinforcing expectations than those who do not teach in a PBIS school. Teachers certified in special education had significantly higher knowledge and competency ratings in relation to maximising structure, using a continuum of strategies to acknowledge appropriate behaviour and employing a variety of techniques to respond to inappropriate behaviour than those not certified in special education. Teachers' knowledge of each of these practices came mostly from in-service sources. Implications of these findings for teachers' preparation in classroom management are discussed.