Introduction Autism Spectrum Disorder (ASD) is a group of disorders that are manifested primarily by difficulties in interpersonal contact. Moreover, children with ASD have specific food habits, which can disturb their proper development. Nowadays, it is suggested that appropriate dietary interventions could help in the treatment of ASD. We will consider how effective a diet could be in this role. Aim This review aims to estimate the effectiveness of dietary interventions used in children with ASD based on scientific research. Material and method This article was created on the basis of a systematic review. Articles were searched using PubMed. The applied terms were: ‘diet in ASD’, ‘dietary interventions in Autism Spectrum Disorder’, ‘Autism Spectrum Disorder’, ‘therapies in ASD’. We searched for studies that were published in less than the last 5 years but older references were also obtained from analyzed articles. Results We received a total of 227 results. After selection, It was decided to use 21 studies with dietetic interventions. Conclusions The most commonly performed interventions are the ketogenic diet, the gluten-free casein-free diet, and probiotic supplementation. Most studies, do not have enough evidence that would allow drawing definite conclusions. Currently, modifying the diet does not appear to have a significant impact on ASD symptoms.