Ōmizo Domain (大溝藩, Ōmizo-han) was a tozama feudal domain under the Tokugawa shogunate of Edo period Japan. It was located in northwestern Ōmi Province, in the Kansai region of central Honshu. The domain was centered at Ōmizo jin'ya, located in what is now the city of Takashima in Shiga Prefecture.