Mount Hiei (比叡山, Hiei-zan) is a mountain to the northeast of Kyoto, lying on the border between the Kyoto and Shiga Prefectures, Japan.
The temple of Enryaku-ji, the first outpost of the Japanese Tendai (Chin. Tiantai) sect of Buddhism, was founded atop Mount Hiei by Saichō in 788. Hōnen, Nichiren, Dōgen and Shinran all studied at the temple before leaving to start their own practices.
The temple complex was razed by Oda Nobunaga in 1571 to quell the rising power of Tendai's warrior monks (sōhei), but it was rebuilt and remains the Tendai headquarters to this day.
The 19th-century Japanese ironclad Hiei was named after this mountain, as was the more famous World War II-era battleship Hiei, the latter having initially been built as a battlecruiser.