Autism Spectrum Disorders (ASD) are neurodevelopmental disturbances affecting social skills, whose incidence worldwide is dramatically increasing. Together with the rise of ASD prevalence, several immune conditions are following the same trend, including Atopic Dermatitis (AD), with a possible clinical relationship with ASD. To date, their pathogenesis is still unknown, but several studies highlighted the relevance of gene-environment interactions to the onset of both disorders. Among potential contributing factors, microRNAs (miRNAs), small molecules capable of controlling gene expression and targeting mRNA transcripts, might represent one of the major circulating link, unraveling the connections between neurodevelopmental and immune conditions. We conducted a systematic literature review, under the PRISMA guidelines, trying to define the panel of common miRNAs involved in both ASD and AD. The review retrieved articles published until December 13, 2018, in PubMed, ScienceDirect, PsycARTICLES and Google Scholar. We found a handful works dealing with miRNAs in ASD and AD, with the most overlapping dysregulated miRNAs being miR-146 and miR-155. Two possible compounds are abnormally regulated in both ASD and AD subjects, possibly cross-contributing to the interactions between the two disorders, setting the basis to investigate more precisely the possible link between ASD and AD from another, not just clinical, perspective.