Literally means "evening or night Mass." As a devotional practice, it refers to the Philippine Catholic tradition of the novena, a series of nine evening Masses usually celebrated during Advent from Dec. 15-23, in preparation for Christmas Day. In the Philippines, the dates are from Dec. 16-24, since Simbang Gabi is held in the early morning.  In the U.S., the practice of the Simbang Gabi has been adapted to local conditions, with the Mass being moved to the evening hours so people can partake in the novena and the Christmas celebrations.

Simbang Gabi traces its roots in Mexico when, in 1587, the Pope granted the petition of Fray Diego de Soria to hold Christmas Mass outdoors because the Church could not accommodate the huge number of people attending the evening Mass. The request was granted and became a permanent practice among Philippine Catholics.  The celebration is also seen as a way of requesting blessings from the Lord, as most people believe that if one completes the whole series of nine dawn masses, their wishes will be granted. Simbang Gabi provides a strong indication of the depth of Catholicism among the people of the Philippines.