Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by deficits in communication, social interaction, and repetitive behaviors. Prenatal exposure to valproic acid (VPA) is a well-established animal model that reproduces autism-like traits. This study aimed to evaluate the possible protective effects of Hericium erinaceus (Lion’s Mane Mushroom, HE) against behavioral and developmental alterations induced by VPA in mice. Forty-eight pregnant C57BL/6 mice were divided into four groups (n=12 each): Control (saline 600 mg/kg, intraperitoneally), VPA (600 mg/kg, intraperitoneally on embryonic day 12), HE (300 mg/kg/day orally throughout pregnancy), and HE+VPA (same HE dose plus 600 mg/kg VPA on E12). Behavioral assessments included developmental milestones (righting reflex, eye opening, body weight), motor coordination (negative geotaxis), locomotor activity (open-field test), repetitive behaviors (cylinder and marble-burying tests), cognitive performance (Y-maze), social interaction (three-chamber test), motivational behavior (splash test), and sensory response (hot-plate test). Results revealed that prenatal VPA exposure caused developmental delay, impaired motor coordination, reduced sociability, hypoactivity, increased repetitive behaviors, and cognitive deficits. In contrast, Hericium erinaceus treatment significantly improved motor development and coordination, enhanced social interaction and exploratory activity, reduced repetitive behaviors, and improved cognitive performance compared to the VPA group. These findings indicate that Hericium erinaceus improved multiple behavioral domains affected by prenatal VPA exposure, including motor, social, and cognitive functions, suggesting a potential preventive neuroprotective role that supports normal neurodevelopment and reduces autism-like behavioral alterations.