List of communities celebrating the Traditional Latin Mass

This is a list of Catholic religious institutes and societies of apostolic life which celebrate the traditional liturgical rites of the Latin Church, mainly the Traditional Latin Mass. This list includes communities which are in communion with the Holy See, as well as groups that are not in full communion with it, with these being demarcated in two main sections. Most use a pre-1970 edition of the Roman Missal, usually the 1962 Missal, but some follow other Latin liturgical rites and thus celebrate not the Roman Rite but a form of liturgy permitted under the 1570 papal bull Quo primum. The pre-1970 Roman Missal was never abrogated by the Catholic Church, yet it was rarely used and sometimes prohibited by local authorities after Vatican II. To clarify the fact that the traditional Roman and other Latin liturgical rites had never been abrogated, and to expand and promote the ancient liturgy's use, Pope Benedict XVI issued in 2007 a motu proprio titled Summorum Pontificum, which was complemented by the instruction Universæ Ecclesiæ in 2011. This superseded previous documents already favorable to the traditional rites: Quattuor abhinc annos and Ecclesia Dei (both by John Paul II). However, Pope Francis abrogated these more expansive permissions in 2021, with the motu proprio Traditionis custodes. This list makes a distinction between those communities using the traditional Roman (or other traditional) rite exclusively, and those which normally celebrate in both forms (modern and traditional) as part of their charism. Those communities using exclusively the traditional rites, may rarely also celebrate or concelebrate Mass in the modern Roman rite, for example, as an external sign of ecclesial communion with a local bishop in the Chrism Mass, or in other particular occasions. However, as the modern Roman rite is not a normal and expected part of their charism, this sporadic celebrations do not turn them into bi-formal for the effects of this classification. As of 2023, the largest priestly communities using the Traditional Latin Mass exclusively are the Priestly Fraternity of Saint Peter (FSSP) with 386 priests, Institute of Christ the King Sovereign Priest (ICKSP) with 147 priests and Institute of the Good Shepherd (IBP) with 62 priests.