Léon-Étienne Duval (November 9, 1903 – May 30, 1996) was a French Cardinal of the Roman Catholic Church. He served as Archbishop of Algiers in Algeria from 1954 to 1988, and was elevated to the cardinalate in 1965.
Léon-Étienne Duval was born in Chênex, Haute-Savoie, and attended the seminary in Annecy before going to Rome, where he studied alongside Marcel Lefebvre at the Pontifical French Seminary. Ordained to the priesthood on December 18, 1926, he then did pastoral work in Annecy until 1942, whilst teaching at the seminary and serving as Director of Works. During World War II, Duval supported the French Resistance and was wary of the Vichy regime. He was an honorary canon and vicar general of Algiers from 1942 to 1946.
On November 3, 1946, Duval was appointed Bishop of Constantine by Pope Pius XII. He received his episcopal consecration on February 11, 1947 from Bishop Auguste Cesbron, with Bishops Raoul Harscouêt and Léon Terrier serving as co-consecrators. Duval was later named Archbishop of Algiers on February 3, 1954.
Duval championed the independence of Algeria, and encouraged peace among Muslims, Christians, and Jews. In early 1962, he denounced the urban warfare that occurred during the Algerian War as "an offence against God," to the anger of the pieds-noirs of his flock, who subsequently called him "Mohammed Duval." Attending the Second Vatican Council from 1962 to 1965, Duval, assisted by Cardinals Julius Döpfner and Raúl Silva Henríquez, delivered one of the closing messages of the Council on December 8, 1965. He also served as President of the North African Episcopal Conference from 1963 to 1988. He was opposed to Action Française, which supported establishing Catholicism as the state religion, because he believed that faith and politics should remain separate. Duval was a schoolmate of the Traditionalist Archbishop Marcel Lefebvre, and in August 1976, Duval urged him to fully submit himself to the authority of the pope.
Pope Paul VI created him Cardinal Priest of S. Balbina in the consistory of February 22, 1965. Duval was one of the cardinal electors who participated in the conclaves of August and October 1978, which selected Popes John Paul I and John Paul II respectively. He occupied Room 86 at the cardinal electors' residence for the August 1978 conclave, sharing a shower with Leo Suenens, Raul Silva, and Juan Ricketts.
Because of his humanitarian and anti-imperialist works, the Cardinal was chosen by the Revolutionary Council as one of four clergymen who would visit the hostages held in the American embassy in Tehran on Christmas Day 1979. On April 19, 1988, he resigned as Algiers' archbishop, after thirty-four years of service.
Duval died in Algiers, at age 92. He is buried in the Basilique de Notre-Dame d’Afrique of that same city. Following his death, John Paul II remarked that, "He will remain a light and an encouragement on a long and difficult road at a moment in which the Christian community in Algeria is facing testing times".