Sekkoji, Buddhist temple in Katsuragi, Japan.

Sekkoji is a Jodo-sect temple in Senno, Katsuragi, Nara Prefecture, with the mountain name Jiunzan and Amida Nyorai as its principal image. Its grounds hold the Hondo, Mirokudo, a garden, a bell tower, a thirteen-story stone pagoda, and the tower's central foundation stone from the late Asuka period.

According to the Engyō shakusho of 1322, a large stone emitting light was found here in the late Asuka period; Emperor Tenji had a Maitreya image carved on it and ordered En no Ozunu to build a hall. Excavations in 1991 uncovered a late Asuka stone seated Buddha, now a Nara Prefecture cultural property, along with roof tiles and a five-by-four bay hall foundation. The temple later became a Jōdo-shū temple.

The temple is nicknamed Somenoji, "the dyeing temple", after the well Somenoi where Princess Chujo is said to have dyed lotus threads in five colours before weaving the Taima Mandala in 763. A cherry tree called Itokake-zakura, where she hung the threads, stands in the grounds, and a statue of the princess is there too.

Sekkoji is not served by rail within walking distance: from Nijo-jinjamaguchi Station on the Kintetsu Minami-Osaka Line it is about five minutes by taxi, and from Kashiba Station on the JR Wakayama Line about ten minutes. By car it lies roughly five kilometres from the Kashihara and Kashiba interchanges of the Nishi-Meihan Expressway. The grounds hold peonies, tree peonies, hydrangeas, cherry and crape myrtle, so flowering periods differ through the year.

The well called Somenoi is where, by legend, Princess Chujo soaked lotus-stem threads and they came out in five colours; she then wove the Taima Mandala in a single night in 763. The cherry tree where she is said to have hung the dyed threads, the Itokake-zakura, stands in the grounds. The earliest record, the 1192 Kenkyū junrei-ki, names no princess: she and her father, Fujiwara no Toyonari, only appear from the Muromachi period.