Children with Down syndrome are at an increased risk for engaging in challenging behaviour that may be part of a behavioural phenotype characteristic of Down syndrome. The methodology of applied behaviour analysis has been demonstrated effective with a wide range of challenging behaviours, across various disabilities. Applications to children with Down syndrome and the examination of behaviourally based strategies to specifically address the unique characteristics of children with Down syndrome are limited. However, there are several studies in which a subset of the participants did have Down syndrome. A handful of these studies are reviewed within the context of functional behaviour assessment and Positive Behavioural Supports. Drawing from these studies and the behavioural literature, as well as the authors' clinical experience and research, suggestions regarding early intervention for challenging behaviour with children with Down syndrome are provided.