"Hark! The Herald Angels Sing" is a Christmas hymn or carol written by Charles Wesley, the brother of John Wesley. It appeared in Hymns and Sacred Poems in 1739. The original opening line was "Hark! how all the welkin rings"; the version known today is the result of alterations by various hands.

The tune that is now used was composed by Felix Mendelssohn in 1840, as part of the cantata Festgesang ("Festival Song") honoring printer Johann Gutenberg and commemorating the invention of his printing press. The cantata was presented at the great festival held at Leipzig. Festgesang's second chorus, "Gott ist Licht" ("God is Light"), was adapted in 1855 by William Hayman Cummings.

The most popular arrangement of the Mendelssohn tune for "Hark! The Herald Angels Sing" is probably that by David Willcocks (published 1961) which adds a descant for the third verse.