Euchaita (Greek: Εὐχάιτα) was a Byzantine town in Pontus, in northern Asia Minor (mod. Turkey). Today the Turkish village Beyözü, in the province of Çorum (in the subprovince of Mecitözü), partly lies on the ruins.
Euchaita was known in Late Antiquity and the Middle Ages as the centre of the cult of Saint Theodore of Amasea, and became a major pilgrimage site after his remains were moved there from neighbouring Amasea. Consequently, its see, originally a suffragan of Amasea, became an archbishopric in the 7th century and a full metropolitan see under Leo VI the Wise (r. 886–912).
In the 5th century, the town was a favourite site of exile for disgraced senior churchmen. In 515, the unfortified town was sacked by a Hunnic raid, after which it was rebuilt, fortified and raised to the status of a city by Emperor Anastasius I. The city was later burned down by the Sassanid Persians in 615, and attacked by the Arabs under Mu'awiya in 640. A second Arab attack captured the city in 663; the raiders plundered the city, destroyed the church of St. Theodore, and wintered there, while the population fled to fortified refuges in the surrounding countryside.
Nevertheless, the city was rebuilt and soon recovered. The Arabs scored a victory in its vicinity in 810, taking captive the local strategos of the Armeniac Theme and his entire treasury. In 972, Emperor John I Tzimiskes renamed the neighbouring Euchaneia, whose exact relation or identity with Euchaita is unclear, into Theodoropolis. The town is recorded as having a vibrant fair during the festival of St. Theodore in the middle of the 11th century, but its history thereafter is unknown.