A Christmas carol (also called a noël) is a carol (song or hymn) whose lyrics are on the theme of Christmas or the winter season in general and which are traditionally sung in the period before Christmas.

The first specifically Christmas hymns for Christians that we know of appear in fourth century Rome. Latin hymns such as Veni redemptor gentium, written by Ambrose, Archbishop of Milan, were austere statements of the theological doctrine of the Incarnation in opposition to Arianism. Corde natus ex Parentis (Of the Father's love begotten) by the Spanish poet Prudentius (d. 413) is still sung in some churches today.

In the ninth and tenth centuries, the Christmas "Sequence" or "Prose" was introduced in North European monasteries, developing under Bernard of Clairvaux into a sequence of rhymed stanzas. In the twelfth century the Parisian monk Adam of St. Victor began to derive music from popular songs, introducing something closer to the traditional Christmas carol.

In the thirteenth century, in France, Germany, and particularly, Italy, under the influence of Francis of Assisi a strong tradition of popular Christmas songs in the native language developed. Christmas carols in English first appear in a 1426 work of John Awdlay, a Shropshire chaplain, who lists twenty five "caroles of Cristemas", probably sung by groups of 'wassailers', who went from house to house. The songs we know specifically as carols were originally communal songs sung during celebrations like harvest tide as well as Christmas. It was only later that carols begun to be sung in church, and to be specifically associated with Christmas.