Currently, no pharmacological treatments ameliorate the core symptoms of autism spectrum disorders, but solely target comorbid symptoms such as irritability, anxiety, and epilepsy. There has been growing interest in using whole cannabis or cannabidiol as potential therapeutics in autism. However, there are concerns surrounding the use of whole cannabis in children, and reports examining the therapeutic efficacy of cannabidiol are inconsistent. In this study, the potential therapeutic efficacy of cannflavin B, a non-psychoactive component of the Cannabis sativa plant, was evaluated. Using prenatal valproic acid (VPA) exposure in rats, a model widely used to study aspects of autism, sex differences in adolescent behaviour, neuronal oscillatory changes, and microglial activity in response to cannflavin B administration (0.2 mg/kg, i.p.) were assessed. Cannflavin B was well tolerated and ameliorated most of the observed VPA-induced changes. Cannflavin B had anxiolytic-like properties in female VPA rats, and normalized sociality in VPA animals of both sexes. Within the prefrontal cortex, cingulate cortex, and hippocampus, most of the VPA-induced regional responses in neuronal oscillatory spectral power, coherence, and theta-gamma cross-frequency synchrony were ameliorated by cannflavin B. Cannflavin B also attenuated the sex- and brain region-specific VPA-induced elevations in the microglial marker Iba1. In vitro , cannflavin B normalized VPA-induced elevations in cortical and hippocampal neuronal activity and promoted more organized cortical firing. These findings demonstrate cannflavin B ameliorates behavioural and neuronal systems function alterations induced by prenatal VPA in rats, and highlights the importance of researching alternative cannabis compounds in autism and other disorders.