A common covarying group of behaviors with ASD are self-injury, aggression, noncompliance, and stereotypies. These problems and related challenging behaviors are problematic in that they are physically dangerous and can impede learning and access to normal activities. Additionally, they require a considerable amount of resources, and compound the difficulty in treating core ASD symptoms. Despite the high profile challenging behaviors present in this population, there has not been a great deal of research regarding assessment, identification, and monitoring of such difficulties. This review covers available empirical based methods for assessing these behaviors. A discussion is provided of potential avenues for future research and clinical practice which is urgently needed for ASD children at this time.