Autism spectrum disorder (ASD) is a diverse neurodevelopmental disorder that commences in early childhood, characterized by enduring social-communication challenges, limited interests, and behavioral rigidity. The management of ASD continues to pose significant difficulties in pediatric practice. Converging evidence implicates abnormalities in synaptic scaffolding and transmission, excitation-inhibition imbalance, mTOR/PI3K-AKT signaling, neuroinflammation, gut-brain axis, and metabolic disturbances, highlighting multiple cellular and molecular targets for potential therapeutic development. Nonetheless, contemporary care is primarily characterized by non-pharmacological interventions and symptomatic pharmacological treatments, with a scarcity of strategies that alter fundamental mechanisms. The blood-brain barrier (BBB) is a significant hurdle to overcome - its structure, transport routes, and context-specific dysfunction in ASD both limit and create opportunities for central nervous system (CNS) drug delivery at the same time. In this context, nanomedicine presents novel opportunities and nanoparticles are currently emerging for various neurological applications in preclinical and clinical studies. They can be designed for targeted drug delivery to the brain, for the development of sophisticated ASD models and for diagnostic and theranostic purposes. This review incorporates the clinical manifestations, mechanistic pathways, BBB biology, and nanoparticle-based methodologies to provide a developmentally informed framework for nano-enabled interventions in ASD.