Animal studies provide a unique opportunity to study the consequences of genetic variants at the behavioural level. Human studies have identified hundreds of risk genes for autism spectrum disorder (ASD) that can lead to understanding on how genetic variation contributes to individual differences in social interaction and stereotyped behaviour in people with ASD. To develop rational therapeutic interventions, systematic animal model studies are needed to understand the relationships between genetic variation, pathogenic processes and the expression of autistic behaviours. Genetic and non-genetic animal model strategies are here reviewed in their propensity to study the underpinnings of behavioural trait variation. We conclude that an integration of reverse and forward genetic approaches may be essential to unravel the neurobiological mechanisms underlying ASD.