St. John of Chicago Orthodox Chapel is an annex of St. Luke Orthodox Church in Palos Hills, Illinois. It has been established as a missionary outreach to those who are seeking to discover the ancient Christian faith as it exists in the 21st century and who live along the Lincoln Way corridor from New Lenox to Frankfort and south to Manhattan, Illinois.
The Sunday service is the Liturgy of St. John Chrysostom which dates from the 4th century but has prayers that predate the Gospels. Other Liturgies used during the year are the Liturgy of St. Basil the Great, also from the 4th century and the Liturgy of the Presanctified Gifts. This Liturgy is traditionally considered to be the work of the 6th-century pope, Saint Gregory of Rome.