The Jesus Prayer (Η Προσευχή του Ιησού) or "The Prayer" (Euchee, Greek: Η Ευχή - the Wish), also called the Prayer of the Heart[3] (Καρδιακή Προσευχή) and "Prayer of the Mind (Nous)" (Νοερά Προσευχή), is a short, formulaic prayer often uttered repeatedly. It has been widely used, taught and discussed throughout the history of the Eastern Churches. The exact words of the prayer have varied from the simplest possible involving Jesus' name to the more common extended form:

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The Jesus Prayer is for the Eastern Orthodox one of the most profound and mystical prayers and it is often repeated continually as a part of personal ascetic practice. Its practice is an integral part of the eremitic tradition of prayer known as Hesychasm (Greek: ἡσυχάζω, hesychazo, "to keep stillness"), the subject of the Philokalia (Greek: φιλοκαλείν, "love of beauty"), a collection of 4th to 15th century texts on prayer, compiled in the late 18th century by St. Nicodemus the Hagiorite and St. Makarios of Corinth. The monastic state of Mount Athos is a centre of the practice of the Jesus Prayer.

While its tradition, on historical grounds, also belongs to the Eastern Catholics, and there have been a number of Roman Catholic texts on the Jesus Prayer, its practice has never achieved the same popularity in the Western Church as in the Eastern Orthodox Church. Moreover, the Eastern Orthodox theology of the Jesus Prayer enunciated in the 14th century by St. Gregory Palamas has never been fully accepted by the Roman Catholic Church. Nonetheless, in the Jesus Prayer there can be seen the Eastern counterpart of the Rosary, which has developed to hold a similar place in the Christian West