Shunseiji, Buddhist temple in Mitaka, Japan.

Shunseiji is a Sōtō Zen temple in Mitaka, Tokyo, founded in 1602 by Ōhara Shunsei. Its main hall, rebuilt in 1993, houses a seated wooden Shakyamuni Buddha. The grounds include a bell tower, a three-story pagoda, and a 3.35-meter seated Buddha statue inaugurated in 1979, modeled on Sri Lankan style.

In 1602 the hatamoto Ōhara Shunsei (Mutei Genshin) of the Aoyama hyakunin-gumi built a thatched hermitage here, giving the temple its name Ōharazan Shunseiji. In 1615 his grandson Shibata Katsushige, granted 500 koku for service at the siege of Osaka, rebuilt it and invited Rankitsu Gyudai of Senshōji in Komae as founding abbot, making that temple its direct head temple. Katsushige died in 1632 and is buried on the grounds.

The temple keeps the Shibata family's memory alive: the graves of Katsushige and three generations of descendants stand in the cemetery, and a stone monument carved in 1796 by the tenth-generation Katsufusa records the family's deeds. The Kannon hall, moved into the west chapel of the main hall, has hosted the August 10 Kannon ceremony since the Keio era, when locals gathered for two nights and three days of nenbutsu chanting. Amida and Koshin prayer groups, practised since before the Meiwa era, still meet.

Shunseiji is at 4-4-22 Shinkawa, Mitaka. From Sengawa Station on the Keio Line it is about 20 minutes on foot; alternatively take the Odakyu bus lines Tak-54 (Sengawa–Mitaka Station South Exit) or Yoshi-03 (Sengawa–Kichijoji Station Central Exit) and get off at Community Center West, roughly 5 minutes from Sengawa.

The temple's Great Buddha was inspired by a 1978 visit to Sri Lanka by abbot Ishizaka and 17 others for a kindergarten opening; moved by drivers stopping to pray at roadside Buddhas, he resolved to build one here. Sculpted by Sri Lankan artist Dayasiri Somapala in Sri Lanka's oldest style, about 2,200 years old, it sits 3.35 m tall and was consecrated in May 1979.