The functional behavioural assessment (FBA) is a process used in identifying the reason (i.e., function) for challenging behaviours when working with students with disabilities and the circumstances and/or environment that reinforce the continued use of the problematic behaviour. However, the procedural definition of the FBA in US federal legislation has been open to interpretation, thus leading to different implementations and the utilization of this advantageous process as a last resort. This article will review the benefits of the FBA process, its impact on the delivery of behavioural interventions for students with disabilities and the significance of early implementation.