'''The Divine Liturgy of St. Gregory''' is one of the liturgies authorized for use by the [[AOCA|Antiochian]] [[Western Rite Vicariate]] (AWRV) and the Western Rite Vicariate of the [[Russian Orthodox Church Outside Russia]]Western Rite Vicariate (RWRV). The AWRV's only authorized text of the [[Mass]] is found in the ''Orthodox Missal''. The basis of the liturgy is the Tridentine Mass as it was celebrated by the [[Society of Clerks Secular of St. Basil]] (SSB), a formerly independent church that formed the basis of the Antiochian Western Rite Vicariate in 1961. The Liturgy of St. Gregory has also been authorized for use by and celebrated within the [[Church of Poland|Polish Orthodox Church]], the [[Church of Russia|Patriarchate of Moscow]], and the [[Church of Alexandria|Alexandrian Patriarchate]].