December 1: World AIDS Day, commemorating those who have died of AIDS, and to acknowledge the need for a continued commitment to all those affected by the HIV/AIDS epidemic.
December 3: International Day of Persons with Disabilities, designed to raise awareness in regards to persons with disabilities in order to improve their lives and provide them with equal opportunity.
December 8: Immaculate Conception of Mary, the Feast of the Immaculate Conception celebrates the solemn celebration, by carious Christian denominations of belief in the Immaculate Conception of the Blessed Virgin Mary.
December 8: Bodhi Day. the Buddhist holiday that commemorates the day that the historical Buddha, Siddhartha Gautama (Shakyamuni), experienced enlightenment, also known as bodhi in Sanskrit and Pali.
December 10: International Human Rights Day, established by the United Nations in 1948 to commemorate the anniversary of the Universal Declaration of Human Rights.
December 12: Feast of Our Lady of Guadalupe, a religious holiday in Mexico commemorating the appearance of the Virgin Mary near Mexico City in 1531.
December 13: St. Lucia's Day, a religious festival of light in Scandinavia and Italy commemorating the martyrdom of St. Lucia, a young Christian girl who was killed for her faith in 304 C.E. She secretly brought food to persecuted Christians in Rome while wearing a wreath of candles on her head so both her hands would be free.
December 16-24: Las Posadas, a nine-day celebration in Mexico commemorating the trials Mary and Joseph endured during their journey to Bethlehem.
December 21: Yule Winter Solstice, celebrated by Pagans and Wiccans. The shortest day of the year represents a celebration focusing on rebirth, renewal and new beginnings as the sun makes its way back to the Earth. A solstice is an astronomical event that happens twice each year when the sun reaches its highest position in the sky.
December 25: Christmas Day, the day that many Christians associate with Jesus' birth.
December 26: Boxing Day, a secular holiday celebrated in the U.K., Canada, Ireland, Australia, New Zealand, Hong Kong and South Africa.
December 26 - January 1: Kwanzaa, an African-American holiday started by Maulana Karenga in 1966 to celebrate universal African-American heritage.
December 26: Zartosht No-Diso (Death of Prophet Zarathushtra), a day of remembrance in the Zoroastrian religion. It is a commemoration of the death anniversary of the prophet Zoroaster, or Zarathushtra.
December 26: St. Stephen's Day, a day to commemorate St. Stephen, the first Christian martyr, or protomartyr.
December 26: Feast of the Holy Family, a liturgical celebration in the Catholic Church in honor of Jesus, his mother and his foster father, St. Joseph as a family. The primary purpose of this feast is to present the Holy Family as a model for Christian families.
December 27: St John's Day, Apostle and Evangelist, the feast day for St. John, celebrated by Christian denominations.
December 28: Feast of the Holy Innocents, a Christian feast in remembrance of the massacre of young children in Bethlehem by King Herod the Great in his attempt to kill the infant Jesus.
December 31: Watch Night, a day for Christians to review the year that has passed, make confessions, and then prepare for the year ahead by praying and resolving.