The diagnosis of Autism spectrum disorder (ASD) is increasing in the population of toddlers. Therefore, there is an emerging number of interventions that aim to ease difficulties caused by this disorder. The aim of this paper was to present a review of literature about the impact of assistive technology, with special emphasis on the use of augmentative and alternative communication (AAC), more precisely communication books and communication boards, on functional communication of people with ASD. High quality assessment of assistive technology increases the success of its implementation and reduces the probability of rejection and abandonment of systems needed for successful functional communication. A review of the literature showed a positive impact on the increase in the acquisition of vocabulary, the frequency of independent expression of wants and needs, and commenting in this population as well as in the population of people with complex communication needs. Sometimes, AAC systems are not applied because of the assumption that they will negatively affect speech development, but research shows that they do not prevent it and in some cases stimulate speech development. Also, the use of communication books and boards has seen positive changes in other areas such as reduced frustration, better emotional regulation, and reduced challenging behaviors. Despite the positive results, there is a need for further research in these areas of functional communication, and especially in the Republic of Croatia where there is almost no research on this topic.