【Objective】 To observe the effects of early postnatal immune activation (EPIA) on social behaviors of male and female mice, and to explore the possible role of the functional state of astrocytes and microglia in this process. 【Methods】 Using lipopolysaccharide (LPS) induced EPIA mice as study subjects, mice were divided into the male-control, male-model, female-control, and female-model groups, each containing 10 mice (n=10). Behavioral tests were performed at 25 - 32 days of age, and the social behavior ability of mice was evaluated by open field test, three-chamber sociability test, and marble burying test. The expression levels of GFAP, IBA-1, TLR4, and NFκB p65 in the cortex and hippocampus were detected by Western blot (n=3). 【Results】 In behavioral tests, social index significantly decreased in LPS treatment group (F=14.907, P<0.05). The interaction effect between treatment and sex was significant in the residence time (F=5.260, P<0.05) and the number of buried marbles (F=7.788, P<0.05). LPS treatment decreased the retention time of the central region in male mice (F=4.261, P<0.05), and increased the number of buried marbles in males (F=20.645, P<0.05). Western blot results showed that LPS treatment increased the expression of GFAP protein in the hippocampus (F=50.443, P<0.05) and cortex (F=30.116, P<0.05), as well as the expression of IBA-1 protein (F=21.844. P<0.05) and TLR4 protein (F=6.215, P<0.05) in the cortex. The results of NFκB p65 showed a significant interaction between treatment and sex in the cortex (F=6.558, P<0.05), and LPS increased the expression of NFκB p65 protein in the cortex in female mice (F=16.317, P<0.05). 【Conclusions】 EPIA is sufficient to induce sex-specific autism spectrum disorder (ASD)-like behavior and enhance astroglial and microglial reactivity in mice. ASD-like behavior induced by EPIA may be related to the TLR4/NFκB signaling pathway in the cortex.