This article contains a list of Encyclicals of Pope Pius XI. Pope Pius XI issued 31 Papal Encyclicals during his reign as Pope and was considering one at his death (number 32 in this list):
| No. | Title (Latin) | Title (English translation) | Subject | Date | |
|---|---|---|---|---|---|
| 1. | Ubi Arcano Dei Consilio | "The Hidden Counsel of God" | "On the Peace of Christ in His Kingdom" | 23 December 1922 | |
| 2. | Rerum Omnium Perturbationem | "All the Disturbing Things" | St. Francis De Sales | 26 January 1923 | |
| 3. | Studiorum Ducem | "On St. Thomas Aquinas" | Thomas Aquinas | 29 June 1923 | |
| 4. | Ecclesiam Dei | "The Church of God" | On St. Jehosophat | 12 November 1923 | |
| 5. | Maximam Gravissimamque | "The Greatest and Gravest" | On French Diocesan Association | 18 January 1924 | |
| 6. | Quas Primas | " " | On the Feast of Christ the King | 11 December 1925 | |
| 7. | Rerum Ecclesiae | "Of the Things of the Church" | Catholic Missions | 8 February 1926 | |
| 8. | Rite Expiatis | " " | On St. Francis of Assisi | 13 April 1926 | |
| 9. | Iniquis Afflictisque | " " | On the Persecution of the Church in Mexico | 18 November 1926 | |
| 10. | Mortalium Animos | "The Minds of Mortals" | On Religious Unity | 6 January 1928 | |
| 11. | Miserentissimus Redemptor | "Most Merciful Redeemer" | Reparation to the Sacred Heart | 8 May 1928 | |
| 12. | Rerum Orientalium | "Of Eastern Things" | Promoting Oriental Studies | 8 September 1928 | |
| 13. | Divini Cultus | " " | On Divine Worship | 20 December 1928 | |
| 14. | Mens Nostra | "Our Mind" | Promotion of the Spiritual Exercises | 20 December 1929 | |
| 15. | Divini Illius Magistri | "That Divine Teacher" | On Christian Education | 31 December 1929 | |
| 16. | Quinquagesimo Ante | "Fifty Years Ago" | On His Priestly Jubilee | 23 December 1929 | |
| 17. | Ad Salutem | "For Salvation" | On St. Augustine | 30 April 1930 | |
| 18. | Casti Connubii | "Chaste Wedlock" | On Christian marriage | 31 December 1930 | |
| 19. | Quadragesimo Anno | "In the Fortieth Year" | On the Reconstruction of the Social Order | 15 May 1931 | |
| 20. | Non Abbiamo Bisogno (Nobis Opus non Est) | "We do not need" | Catholic Action in Italy | 29 June 1931 | |
| 21. | Nova Impendet | "A New Scourge Threatens" | On the Economic Crisis | 2 October 1931 | |
| 22. | Lux Veritatis | "The Light of Truth" | On the Council of Ephesus | 25 December 1931 | |
| 23. | Caritate Christi Compulsi | "The Love of Christ Impels Us" | On the Sacred Heart | 3 May 1932 | |
| 24. | Acerba Animi | "Sorrow of Soul" | On the Persecution of the Church in Mexico | 29 September 1932 | |
| 25. | Dilectissima Nobis | "Most Dear to Us" | On the Persecution of the Church in Spain | 3 June 1933 | |
| 26. | Ad Catholici Sacerdotii | "To the Summit of Catholic priesthood" | On the Catholic priesthood | 20 December 1935 | |
| 27. | Vigilanti Cura | "Vigilant Care" | On Motion Pictures | 29 June 1936 | |
| 28. | Mit Brennender Sorge (Cura Ardens) | "With Burning Anxiety" | On the Church and the German Reich | 14 March 1937 | |
| 29. | Divini Redemptoris | "Of a Divine Redeemer" | On Atheistic Communism | 19 March 1937 | |
| 30. | Nos Es Muy Conocida | "It Is Well Known to Us" | On the Religious Situation in Mexico | 28 March 1937 | |
| 31. | Ingravescentibus Malis | "The Increasing Evils" | On the Rosary | 29 September 1937 | |
| 32. | Humani Generis Unitas | "On the Unity of the Human Race" | On the Church and Antisemitism, Racism and the Persecution of Jews | Never been promulgated |