Lumen fidei (The Light of Faith) is the first encyclical of Pope Francis, issued on 29 June 2013, the Solemnity of Saints Peter and Paul, and published on 5 July 2013, less than four months after his election to the papacy.

It was issued in conjunction with the Year of Faith proclaimed by Pope Benedict XVI to be observed from October 2012 to November 2013.

[1] According to Francis X. Rocca, "Pope Francis' first encyclical, 'Lumen Fidei' ("The Light of Faith"), is a celebration of Christian faith as the guiding light of a 'successful and fruitful life', inspiring social action as well as devotion to God, and illuminating 'every aspect of human existence', including philosophy and the natural sciences.

[3] Francis worked from a first draft completed by Benedict before his resignation[3] and makes the authorship clear: "These considerations on faith – in continuity with all that the Church's magisterium has pronounced on this theological virtue – are meant to supplement what Benedict XVI had written in his encyclical letters on charity and hope.

"[5] Part of the purpose of the encyclical is to restore the light of faith to an understanding of its place in the common journey of mankind.