Positive and proactive approaches to behaviour support have been recognised as one component required to create effective and inclusive school environments (Finkelstein et al., 2019). States and territories within Australia have increasingly adopted schoolwide positive behavioural interventions and supports (SWPBIS) as a means to creating effective social and behavioural change (Poed & Whitefield, 2020). However, ensuring staff implement SWPBIS as it is intended has been a challenge, both in Australia and internationally (McIntosh et al., 2016; NSW Ombudsman, 2017). The current study identifies and seeks to address two gaps in the existing literature exploring noted barriers to the successful and sustained implementation of SWPBIS. First, limited exploration of teachers' perceptions of their preparation (pre-service and in-service) and confidence to engage in SWPBIS practices and supports has been undertaken in Australia. Additionally, the degree to which teachers agree with a functional approach to understanding and supporting student behaviour has not been undertaken in an Australian context. The findings from such exploration may be used to inform the development of teacher training programs, and support efforts to successfully and sustainably implement SWPBIS in Australian schools.