Honzan-ji, Buddhist temple in Misaki, Japan.

Honzan-ji is a Tendai temple on Mount Iwama in Misaki, Okayama Prefecture, founded in 701 and moved to its present site in 1110. Its main hall, built in 1350, has a cypress-bark roof, and the three-storey pagoda of 1652 is the largest in Okayama Prefecture. The grounds also hold a 1335 stone pagoda, a 1519 hall, a 1686 gate and a mausoleum of the Tsuyama lords.

According to temple tradition, the monk Saeki Ariyori founded a temple called Shinzan-ji on a summit south of the present site in 701, and about fifty years later the Chinese monk Jianzhen renamed it Honzan-ji. In 1110 it was moved to its current location and flourished as a Tendai mountain training centre with up to 120 monks' quarters. In 1132 the parents of Hōnen prayed there for a safe childbirth. In the Edo period it became a prayer temple of Tsuyama Domain, and the Mori and later Matsudaira lords built their mausoleum in the grounds.

The temple's name was changed from Shinzan-ji to Honzan-ji by the Tang-dynasty monk Jianzhen (Ganjin), according to temple tradition. In 1132 the parents of Hōnen, Uruma Tokikuni and his wife, came here to pray for a safe childbirth. The precinct once held as many as 120 monks' quarters, and the temple was a mountain training centre of Tendai esoteric Buddhism.

By car, the temple is about 30 minutes south of the Tsuyama Interchange on the Chugoku Expressway. By train, get off at Yuge Station on the JR Tsuyama Line and continue about 15 minutes by car. The approach and grounds involve slopes and stone steps, so allow time for walking between the halls.

The oldest structure still standing on the grounds is a stone hōkyōintō pagoda dated to 1335, predating the main hall by fifteen years. A second hōkyōintō in front of the mausoleum was built in 1399. Both are designated cultural properties, the first nationally and the second by Okayama Prefecture.