Autism spectrum disorders (ASD) represent a heterogeneous group of neurodevelopmental disorders which are both severe and frequent. Understanding its pathophysiology could lead to identifying promising new markers and treatments. For years, a growing number of studies have pointed to an important involvement of the immuno-inflammatory system in ASD. Extensive reviews have already addressed this topic. Yet, this field of investigations is not well known to practitioners even those working with ASD patients. Our main objective is to provide an introduction to these new insights through a mini review of the literature. A first field of antenatal studies connects fetal features and maternal infections to ASD by means of the participation of maternal immune activation (MIA) associated with the production of a particular pro inflammatory cytokinic profile with IL-1, IL-6 and TNF and IL-17. Maternal autoantibodies and other immune-related disorders can also lead to impairment of fetal neurodevelopment. Other postnatal studies have shown the correlation between ASD and autoantibodies and between ASD and inflammatory environment through impaired interleukin levels (IL-6 being the most extensively investigated). Disruption of intestinal microbiota appears to be a possible pathogenic mechanism of ASD. The growing paths opened recently between immunology and psychiatry appear to be promising in the understanding of ASD. It could eventually participate in the development of diagnostic markers and help the emergence of new personalized therapeutics suitable for these patients.