Mater et Magistra
- Christianity and Social Progress. Deplores the arms race and addresses the economic disparity between nations. Encyclical promulgated 15 May, 1961.
- http://www.papalencyclicals.net/John23/j23mater.htm

Pacem in Terris
- Peace on Earth. Catholic social teaching. Peace must be based on rights and responsibilities. First encyclical addressed to all people, not only Christians. Promulgated 11 April, 1963.
- http://www.papalencyclicals.net/John23/j23pacem.htm

Meditation for the Feast of St. Francis of Assisi
- Brief reflection on how Francis followed Christ, and the implications for us.
- http://www.catholic-forum.com/saints/pope026105.htm

Meditation for the Feast of the Guardian Angels
- Excerpts. Published 2 October, 1959.
- http://www.catholic-forum.com/saints/pope026104.htm

Princeps Pastorum
- On the Missions. Encyclical promulgated 28 November, 1959.
- http://www.ewtn.com/library/ENCYC/I23PRINC.HTM

Ad Petri Cathedram
- On Truth, Unity and Peace, in a Spirit of Charity. John XXIII's first encyclical. Promulgated 29 June, 1959.
- http://www.ewtn.com/library/ENCYC/I23PETRI.HTM

Paenitentiam Agere
- On Penance. Encyclical promulgated 1 July, 1962.
- http://www.ewtn.com/library/ENCYC/I23PAENI.HTM

Grata Recordatio
- On the Rosary. Encyclical promulgated 26 September, 1959.
- http://www.catholic-forum.com/saints/bvm00001.htm

Aeterna Dei Sapientia
- On St. Leo the Great. Encyclical of Pope John XXIII promulgated on 11 November, 1961.
- http://www.catholic-forum.com/saints/stl04001.htm

Sacerdotii Nostri Primordia
- Encyclical on St. John Vianney, promulgated 1 August, 1959.
- http://www.catholic-forum.com/saints/stj18001.htm

Encyclicals
- Full text of all of John XXIII's encyclicals, with concordances and word frequency lists. Each chapter in its own file.
- http://www.intratext.com/X/ENG0069.htm