The genus Mesopsocus Kolbe from Japan are reviewed with some records from Far East and Taiwan. Four species are recognized: Mesopsocus dislobus sp. nov., M. unipunctatus (Mčller, 1880), M. laticeps (Kolbe, 1880), and M. hongkongensis Thornton, 1959. The latter two species are newly recorded from Japan. A key to Japanese species of the genus Mesopsocus is given.