Purpose: School-wide positive behaviour support (SWPBS) is a proactive behavioural support system that fosters behaviour change in individuals in a school setting. This article aims to present a case example of teaching and reinforcing behavioural expectations in a special school. Design/methodology/approach: This case study reflects different steps and materials used before and during the intervention in a special education school with 61 secondary students with intellectual disabilities. An AB design (A – baseline; B – intervention) was used to collect and analyze data. Findings: Results suggest that teaching behavioural expectations as a universal measure may be feasible and positively impact school climate. Suggestions and recommendations for implementing SWPBS within a school are provided. Originality/value: This case study provides a step-by-step guide illustrating the process of teaching and reinforcing behavioural playground expectations to young adults with intellectual disabilities attending a special school.