Despite the Tridentine Mass being supplanted by a new form of the Roman Rite Mass, some communities continued celebrating pre-conciliar rites or adopted them later. This includes priestly societies and religious institutes which use some pre-1970 edition of the Roman Missal or of a similar missal in communion with the Holy See. In the following list, all societies are considered canonically regular by, and in full communion with, the Catholic Church, so groups such as the Society of Saint Pius X (SSPX) and Congregation of Mary Immaculate Queen (CMRI), respectively, are not included. Most use a pre-1970 edition of the Roman Missal, usually 1962 Missal, but some follow other Latin liturgical rites and thus celebrate not the Tridentine Mass but a form of liturgy permitted under the 1570 papal bull Quo primum.

The use of a pre-1970 Roman Missal has never been prohibited by the Catholic Church. Despite never being suppressed by the Church, it was rarely used post-Vatican II. To clarify the fact that the Extraordinary Form of the Roman Rite has never been abrogated and expand the liturgy's use, Pope Benedict XVI issued in 2007 a motu proprio titled Summorum Pontificum. In 2021, Pope Francis abrogated these more expansive permissions with his motu proprio Traditionis custodes, seeking to emphasize the celebration of the more commonly used Ordinary Form of the Mass.

Many of these communities describe themselves as traditionalist.