In 2010, the New Zealand Ministry of Education introduced Positive Behaviour for Learning – School-wide (PB4L-SW) in response to growing concerns about the reported increase in the number of children and youth engaged in persistent, antisocial behaviour. This framework focuses on improving primary and secondary schools’ capacity to prioritise student wellbeing and positive behaviour and is being implemented in over 600 schools throughout New Zealand. While there are initial evaluations of the framework at the systems level, there is little evidence of the fidelity with which teachers are implementing PB4L-SW in their classrooms. The aims of this research project were; (1) to investigate the effects of teacher coaching on the fidelity of PB4L-SW procedures across the school, (2) to investigate the experiences of classroom teachers when using PB4L-SW procedures in the classroom and, (3) to determine whether the School-wide Evaluation Tool (SET) and the Office Discipline Referrals (ODR) provide enough data to determine the level of fidelity with which teachers are implementing PB4L-SW in the classroom or if further evaluation measures are needed. Six members of one school’s PB4L-SW leadership team and nine teachers from the same school participated. Results of this research found that even though the school was implementing PB4L-SW with strong fidelity, as seen by the results from the SET and office discipline referrals (ODRs), confusion still existed around the framework amongst members of the teaching team. Some teachers needed further support to assist them to embed the framework seamlessly into their practice. The implications of these findings are discussed.