Moni Sagmata, Orthodox monastery in Boeotia, Greece

Moni Sagmata is an Orthodox men's monastery of the Metropolis of Thebes and Livadeia, built at 747 m on Mount Sagmation, above the Boeotian plain east of Thebes. Its centre is a cross-in-square church of the Transfiguration raised in 1106 under Alexios I Komnenos; a chapel of St Nicholas stands 150 m to the south, and a newer chapel nearby holds the relics of St Clement of Athens.

The monastery was founded in the 12th century by Saint Clement of Athens on the site of an ancient sanctuary of Zeus Hypatos, whose building material was reused. Emperor Alexios I Komnenos funded it and gave it rich gifts and privileges, including a relic of the True Cross. The main church was built in 1106. It was looted during the German Occupation and restoration began in the 1970s.

The monastery is dedicated to Saint Clement of Athens, its 12th-century founder, whose memory is kept on 26 January and 1 May. A chapel and museum honour Saint Luke of Crimea (1877–1961), displaying his personal belongings and icons. The monastery also runs an Orthodox children's camp.

The monastery stands at 747 m on Mount Sagmatas, reached by an unpaved road from the village of Ypato. It is open daily 7:30–13:00 and 16:00 until sunset. The steep gorge edge and rough track call for sturdy shoes.

The mountain was originally known as Ypation Oros but was renamed Sagmation when the monastery became established there. The new name reflects the saddle-like shape of the ridge that defines the landscape.