Autism Spectrum Disorder (ASD) is a multifaceted neurodevelopmental condition characterized by deficits in social communication, repetitive behaviors, and restricted interests. Emerging evidence suggests that gut-brain axis a dynamic, bidirectional communication network between gut microbiota and central nervous system, is critical in shaping behavioral ontogeny in ASD. Dysbiosis of gut microbiota, commonly observed in individuals with ASD, has been associated with alterations in neurodevelopmental trajectories and symptom severity. Furthermore, disturbances in maternal microbiome during pregnancy are increasingly recognized as key factors influencing fetal brain development, potentially heightening risk of ASD and behavioral manifestations. Mechanistic research reveals that gut-derived metabolites modulate blood-brain barrier integrity, neuroinflammatory processes, and neuronal circuit formation, contributing to behavioral outcomes. These findings emphasize gut microbiota's profound influence on emergence and progression of ASD-related behaviors. Promising therapeutic strategies, including probiotics, prebiotics, fecal microbiota transplantation, and dietary interventions, have demonstrated potential in modulating the gut microbiome and improving behavioral symptoms in ASD. However, challenges such as individual variability in microbiome composition, limited clinical evidence, and an incomplete understanding of causative mechanisms remain significant barriers to clinical translation. This review explores the interplay between gut microbiota and ASD-associated behaviors, focusing on key mechanisms such as microbial regulation of neurotransmitter production, immune signaling, and neuroinflammation. It further highlights gut microbiota's potential as a modifiable factor influencing neurodevelopmental and behavioral outcomes in ASD. By advancing our understanding of gut-brain axis, we can pave the way for personalized and targeted interventions aimed at improving behavioral ontogeny and developmental trajectories in individuals with ASD.
