"Executive function" is an umbrella term for functions such as planning, working memory, impulse control, inhibition and mental flexibility, as well as for the initiation and monitoring of action. The primacy of executive dysfunction in autism is a topic of much debate, as are recent attempts to examine subtypes of executive function within autism and other neurodevelopmental disorders that are considered to implicate frontal lobe function. This article will review cognitive behavioural studies of planning, mental flexibility and inhibition in autism. It is concluded that more detailed research is needed to fractionate the executive system in autism by assessing a wide range of executive functions as well as their neuroanatomical correlates in the same individuals across the lifespan.