This article contains a list of encyclicals of Pope Pius XI. Pius XI issued 31 papal encyclicals during his reign as pope and was considering one at his death.
| No. | Title (Latin, except where is noted) | 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 | "Disturbance of All Things" | 26 January 1923 | ||
| 3. | Studiorum ducem | "On St. Thomas Aquinas" | 29 June 1923 | ||
| 4. | Ecclesiam Dei | "The Church of God" | 12 November 1923 | ||
| 5. | Maximam gravissimamque | "The Greatest and Gravest" | On French Diocesan Association | 18 January 1924 | |
| 6. | Quas primas | " " | 11 December 1925 | ||
| 7. | Rerum Ecclesiae | "Of the Things of the Church" | Catholic Missions | 28 February 1926 | |
| 8. | Rite expiatis | " " | 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" | 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" | 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" | 30 April 1930 | ||
| 18. | Casti connubii | "Chaste Wedlock" | 31 December 1930 | ||
| 19. | Quadragesimo anno | "In the Fortieth Year" | On the Reconstruction of the Social Order | 15 May 1931 | |
| 20. | Non abbiamo bisogno (in Italian) | "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" | 25 December 1931 | ||
| 23. | Caritate Christi compulsi | "The Love of Christ Impels Us" | 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" | 20 December 1935 | ||
| 27. | Vigilanti cura | "Vigilant Care" | On Motion Pictures | 29 June 1936 | |
| 28. | Mit brennender Sorge (in German) | "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 (in Spanish) | "It Is Well Known to Us" | On the Religious Situation in Mexico | 28 March 1937 | |
| 31. | Ingravescentibus malis | "The Increasing Evils" | 29 September 1937 |
At the time of his death, Pius XI was reviewing an early version of an additional encyclical, Humani generis unitas (On the Unity of the Human Race), on the church, anti-Semitism, racism, and persecution of Jews.