Latrocinium is a ecclesiastical Latin word meaning 'rebel or hostile council'. It literally means 'robber council.' The infamous Council of Sirmium is a latrocinium. Another is the Synod of Pistoia.

Richard I of England exempted the Knights Templar from Latrocinium and murdrum amongst other privileges.

Conservative catholics associated with sedevacante movements such as the United States-based true Catholic Church under Reverend Father Earl Lucian Pulvermacher (proclaimed Pope Pius XIII by his supporters) regard the Vatican II as a Latrocinium, given its alleged role in a fundamental revision of Roman Catholic beliefs and ritual, notably the replacement of the Tridentine Mass by the Novus Ordo (vernacular Mass) with the resulting greater participation of the laity in the ceremony and the reordering of church sancturies. They argue that many of the fundamental documents of Vatican II contradict earlier Church dicta and papal bulls, including the Quo Primum Papal Bull of 1570 and the Syllabus of Errors of Pope Pius IX.

However few mainstream members of the Roman Catholic Church, no senior members of the hierarchy and none of the popes during or after the Council (Popes John XXIII, Paul VI, John Paul I and John Paul II) accept the belief that Vatican II was a Latrocinium. Vatican II, its documents and the Novus Ordo remain central to modern day Roman Catholicism.