Cantata no. 110: Unser Mund sei voll Lachens, BWV.110

Unser Mund sei voll Lachens ('May our mouth be full of laughter'), BWV 110, is a church cantata by Johann Sebastian Bach. He composed the Christmas cantata in Leipzig for Christmas Day and first performed it on 25 December 1725.

When Bach wrote the music, he was in his third year as Thomaskantor, the church music director of Leipzig. After months with only a few cantata compositions, he embarked on a set of five cantatas for Christmas occasions. In four of these, he used earlier texts published in 1711 by Georg Christian Lehms. The text for this cantata has no pairs of recitative and arias as is common in Baroque opera and contemporary Bach cantatas. Using an older style, it instead features three biblical quotations – verses from Psalm 126, a verse from the Book of Jeremiah about God's greatness, and the angels' song from the Nativity according to the Gospel of Luke – alternating with arias. The closing chorale is from Kaspar Füger's hymn "Wir Christenleut".