Individuals with autism spectrum disorder (ASD) exhibit long-standing impairments in social interaction, limited areas of interest, and repetitive behaviors. The complexity of ASD stems from multiple factors, including genetic, epigenetic, immunological, and environmental variables. The current treatment methods primarily focus on alleviating symptoms, necessitating the development of novel therapies that directly address the underlying biological cause of this condition. In recent years, mesenchymal stem cells (MSCs) have been found to produce therapeutic effects through paracrine signaling, which has brought the concept of cell-free therapy to the forefront of regenerative medicine. Exosomes, nanoscale extracellular vesicles rich in proteins, lipids, and RNAs, represent a vital element of the MSC secretome and are considered potent regulators of intercellular communication for inflammatory processes, neurogenesis, and synaptic remodeling. MicroRNAs (miRNAs), which are components of exosomal cargo, are crucial because they can post-transcriptionally modify gene expression, thereby affecting essential pathways associated with neurodevelopment. Exosomal miRNAs originating from MSCs significantly contribute to the interplay between neurology and immunology, providing a cell-free and potentially safer alternative to conventional stem cell therapies. The evolving roles of MSC-derived exosomal miRNAs in relation to ASD continue to be investigated. Current preclinical evidence supporting the fundamental properties of MSCs and their exosomes, critical miRNAs associated with ASD pathogenesis, and their therapeutic potential, as well as recent advances in stem cell biology, exosome technology, and neuroscience research, aims to illuminate a promising area for ASD treatment.