Omi (近江国; -no kuni) is an old province of Japan, which today comprises Shiga prefecture. It was a key station on the Tokaido road.

The ancient capital was near Otsu, which was also a major castle town. During the Sengoku period, the northern part of the province was the fief of Ishida Mitsunari, Tokugawa Ieyasu's opponent at the Battle of Sekigahara, although he spent most of his time in Osaka Castle administering the fief of Toyotomi Hideyoshi's young son. After Ishida's defeat, Tokugawa granted the fief to his allies, the Ii clan , who built the castle and town of Hikone on the ruins of Sawayama.