Marcel Thomas Rooney (born September 20, 1937) is an American Benedictine monk, abbot, liturgist, musician, and author. He is a member of Conception Abbey located in Conception, Missouri, which is part of the Swiss-American Congregation. He previously was elected and served as the eight Abbot Primate of the Benedictine Confederation of the Order of Saint Benedict. He was elected to his position as Abbot Primate in 1996 and resigned in 2000.