Maternal obesity is reported to increase risk for metabolic diseases in offspring. Furthermore, recent research suggests that maternal obesity also affects the central nervous system in offspring, but a mechanism is unclear. The present study examined the effects of maternal obesity on central nervous system function in offspring. Female 8-week-old C57BL/6J mice were fed with a high-fat diet (HFD) or a regular diet (RD) for 4 weeks and mated with male 8-week-old C57BL/6J mice. The experiments were conducted when offspring reached 8 weeks of age. In the social interaction test, interaction time with a stranger mouse in female offspring of mice fed with HFD was reduced compared to female offspring of mice fed with RD; no such effect was observed in male offspring. These results suggest that only female offspring of obese mice show impairment in social behavior. The mRNA levels of estrogen receptor alpha in the amygdala, which regulates social behavior, were reduced in female offspring of mice fed with HFD, while plasma estradiol levels were unchanged. In addition, the estrogen receptor antagonist fulvestrant reduced interaction time with a stranger mouse. Taken together, our results suggest that maternal obesity impairs social behavior in female offspring by decreasing central estrogen function.