Several species of animals, including horses and pigs, can be infected with Japanese encephalitis virus (JEV). Wild boars (Sus scrofa) are also considered to be an effective amplifying host for JEV in wild environments. In this study, 288 blood samples were collected from wild boars in eight Korean provinces, and antibodies against JEV were detected using a virus neutralizing assay. The results showed that 66.0% (190/288) of wild boars in Korea had neutralizing antibodies against JEV. We found no significant differences in the seroprevalence of JEV among provinces (p > 0.05). The results indicate that wild boars in Korea have been exposed to JEV, suggesting that these boars may play an important role in amplifying and carrying JEV to other regions of Korea. The result of this study may be helpful for planning preventive measures.