Epilepsy and autism spectrum disorders (ASDs) frequently co-occur during childhood, however, the characteristics of psychiatric or behavioural problems in these children remains largely unknown. This article contributes to these discussions by reporting on the prevalence and presentation of psychiatric or behavioural problems in children with epilepsy and ASDs, as well as on the use of anticonvulsants in these children. The current evidence suggests that children with epilepsy and ASDs may present with a distinct clinical profile, with a greater number of developmental difficulties, and a more severe expression of the ASD phenotype that can not solely be accounted for by level of intellectual functioning. Positive effects of anticonvulsants on behavioural symptoms associated with ASDs were also reported, though pharmacoresistance and a lack of clear treatment guidelines may contribute to an elevated risk of adverse side effects. In relation to clinical presentation and management there is a need for careful consideration of potential interaction effects between disorder specific factors (e.g., age of seizure onset/ASD diagnosis), cognitive characteristics (e.g., intellectual functioning, memory), and psychosocial variables (e.g., coping strategies). Ultimately however, many conclusions are tentative and this review highlights the need for more empirically validated research on children with epilepsy and ASDs.