Autism spectrum disorder (ASD) is neurodevelopmental disorders characterized by the sociability deficit and repetitive behavior. We focus on allopregnanolone (ALLO), a neurosteroid synthesized from progesterone, as a candidate factor for the onset of ASD. In our previous reports, SKF105111 (SKF), an inhibitor of 5α-reductase type I and II, induced a decline in brain ALLO content and ASD-like behaviors in not female but male mice. We also demonstrated that brain ALLO content decline and sociability deficit also appear in ovariectomized (OVX) mice. In this study, we analyzed the effects of SKF on ASD-like symptoms in OVX mice. Six-week-old mice received ovariectomy, and SKF (40 mg/kg, i.p.) were treated before 3 hours starting each behavioral test. Contrary to our expectations, brain ALLO content decline was reversed by SKF in OVX mice. SKF also attenuated OVX-induced sociability deficits and social anxiety-like behavior from the results of the 3-chamber, resident-intruder, and mirror-chamber test. These results suggest that SKF improves ASD-like symptoms of OVX mice in contrast to male mice's results. The different susceptibilities to SKF between male and female mice may give us a new insight into the sexual difference in the incidence of ASD.