Autism spectrum disorder (ASD) is associated with immune alterations and neuroinflammation. Increasing endocannabinoid tone attenuates ASD-related behavioural changes in rodent models and modulates Toll-like receptor (TLR)-induced neuro-immune responses. This study examined the effect of TLR3 activation, in the presence or absence of a fatty acid amide hydrolase (FAAH) inhibitor, on neuroinflammatory gene expression and endocannabinoid levels, in a preclinical rodent model of ASD. Female Sprague-Dawley rats prenatally exposed to either saline or valproic acid (VPA) received 1) the TLR3 agonist and viral mimetic polyI:C (3mg/kg) or saline-vehicle and were euthanised 4h later OR 2) the FAAH inhibitor PF3845 (10mg/kg) or vehicle, prior to polyI:C or saline-vehicle, and underwent testing for nociceptive (hot plate test) & social responding (3-chamber test) behaviour 24h later and euthanised immediately after. Endocannabinoid, N-acylethanolamine and inflammatory gene expression levels were assessed in the prefrontal cortex (PFC). PolyI:C increased pro-inflammatory gene expression in saline-exposed rats at 4h and 24h. At 4hrs, polyI:C-induced increases in Il-1β, Ccl2 and Cxcl10 expression were significantly lower in VPA- versus saline-exposed counterparts. At 24hrs, polyI:C-induced increases in expression of Cxcl10 and markers of pro-inflammatory astrocytes, Gfap and C3, were reduced in VPA- versus saline-exposed rats. PF3845 increased N-acylethanolamine levels but did not alter nociceptive responding, social behaviour or PFC inflammatory gene expression in polyI:C-treated saline- or VPA-exposed rats. In conclusion, VPA-exposed female rats exhibit blunted TLR3-induced inflammatory responses in the PFC, an effect unaltered by FAAH inhibition. These data confirm altered neuroimmune responding to a viral mimetic in this model of ASD.