An apostolic constitution (Latin constitutio apostolica) is the highest level of decree issued by the Pope of the Catholic Church. The use of the term constitution comes from Latin constitutio, which referred to any important law issued by the Roman emperor, and is retained in church documents because of the inheritance that the canon law of the Roman Catholic Church received from Roman law.

By their nature, apostolic constitutions are addressed to the public. Generic constitutions use the title Apostolic Constitution, and treat on solemn matters of the church, such as the promulgation of statutes or definitive teachings. The forms Dogmatic Constitution and Pastoral Constitution are titles sometimes used to be more descriptive as to the document's purpose.

Apostolic Constitutions are issued as Papal bulls due to their solemn, public form. The next highest category, after an Apostolic Constitution, is an Encyclical Letter.

Examples of apostolic constitutions

16th Century

• Quo primum (1570) Pius V's Apostolic constitution on the Tridentine Mass

19th Century

• Ineffabilis Deus (1854) Pius IX's dogmatic constitution on the Immaculate Conception of Mary.

• Ad Universalis Ecclesiae (1862) Pius IX's papal constitution dealing with the conditions for admission to religious orders of men in which solemn vows are prescribed

20th Century

• Bis Saeculari (1948), Pope Pius XII on Sodality of Our Lady.

• Munificentissimus Deus (1950) Pius XII's dogmatic constitution on the Assumption of Mary.

• Exsul Familia (1952) Pius XII's constitution on migration

• (1962) John XXIII's Apostolic constitution on the promotion of the study of Latin

• Paenitemini (1966) Paul VI's Apostolic constitution on Fasting and Abstinence in the Roman Catholic Church.

• Missale Romanum (1969) Paul VI's Apostolic constitution on the revised liturgy

• Romano Pontifici eligendo (1975) Paul VI's Apostolic constitution on the election of the Roman pontiff

• (1982) John Paul II's Apostolic constitution raising Opus Dei to the rank of a personal prelature

• (1983) John Paul II's constitution instituting the 1983 Code of Canon Law

• Pastor Bonus (1988) — John Paul II's rules on the re-organisation of the Roman Curia

• Ex corde ecclesiae (1990) — John Paul II's rules on Catholic universities

• (1992) John Paul II's Apostolic constitution on the new Catechism of the Catholic Church

• Universi Dominici gregis (1996) — John Paul II's rules on electing the Roman pontiff

21st Century

• Anglicanorum Coetibus, (2009) - Benedict XVI's rules for providing for personal ordinariates for Anglicans entering into full communion with the Catholic Church.