它是基督徒庆祝耶稣基督诞生的庆祝日。根据天主教的福音书，耶稣是伯利恒的圣母玛利亚受圣灵感孕後生下的，玛利亚和丈夫约瑟当时正在去罗马人口普查注册的路上。耶稣的出生在信徒看来是犹太教预言中的默西亚将要到来计划的实现，因为伯利恒是约瑟祖先大卫一族的家。
圣诞节的英語Christmas，即「基督弥撒」。有时又缩写为「Xmas」。這可能是因为 X 类似于希腊字母 Χ（Chi）；Χ 是「基督」的希腊语 Χριστόςì（Christos）中的首個字母。有人認為這可能是因為近年來西方多元文化的興起，為了尊重其它信仰的人士，以淡化聖誕節的宗教色彩。荷蘭語名稱類似英語，稱作Kerstmis，常縮短為Kerst。
聖誕節西班牙語稱為Navidad，葡萄牙語稱為Natal，波蘭語稱為Boże Narodzenie，法語稱為Noël，意大利語稱為Natale，加泰羅尼亞語稱為Nadal，意思是「誕生」，更清晰地反映聖誕節的意思。與此相對，德語稱為Weihnachten，意思僅為「神聖的夜晚」。
The word Christmas originated as a compound meaning "Christ's Mass". It is derived from the Middle English Christemasse and Old English Cristes mæsse, a phrase first recorded in 1038."Cristes" is from Greek Christos and "mæsse" is from Latin missa (the holy mass). In Greek, the letter Χ (chi), is the first letter of Christ, and it, or the similar Roman letter X, has been used as an abbreviation for Christ since the mid-16th century.Hence, Xmas is often used as an abbreviation for Christmas.
路加描述说，玛利亚年幼时收到天使加百利的消息，身为處女的她藉由圣灵受孕。当时罗马皇帝奥古斯都有下旨，叫天下人民各归各城人口普查，于是她和丈夫约瑟离开在加利利的拿撒勒城上犹太去，这是居里扭作叙利亚总督之後，头一次报名上册，途中他们经过约瑟祖先大卫生活的伯利恒城，在伯利恒因为在乡村旅店已经没有空房，他们只好寄宿在旅舍外面，玛利亚在那儿的马厩里生下了耶稣，这里的“马厩”根据圣经版本不同而不同，但通常是一个喂食槽或是个畜栏。基督出生在伯利恒，伯利恒是约瑟祖先大卫王的家，这就实现了以色列的预言。後来耶稣家逃到埃及是为了逃避愤怒的大希律王的追杀，因为希律王听说了在伯利恒出生一个新的犹太王。当希律王死后，新的犹太王继位，他并不认识耶稣和他的父母，因此耶稣的生命就没有了威胁，这样耶稣和家人返回了以色列，他们定居在拿撒勒。
In Christianity, Christmas is the festival celebrating the Nativity of Jesus, the Christian belief that the Messiah foretold in the Old Testament's Messianic prophecies was born to the Virgin Mary. The story of Christmas is based on the biblical accounts given in the Gospel of Matthew, namely Matthew 1:18-Matthew 2:12 and the Gospel of Luke, specifically Luke 1:26-Luke 2:40. According to these accounts, Jesus was born to Mary, assisted by her husband Joseph, in the city of Bethlehem. According to popular tradition, the birth took place in a stable, surrounded by farm animals, though neither the stable nor the animals are specifically mentioned in the Biblical accounts. However, a manger is mentioned in Luke 2:7, where it states, "She wrapped him in cloths and placed him in a manger, because there was no room for them in the inn." Early iconographic representations of the nativity placed the animals and manger within a cave (located, according to tradition, under the Church of the Nativity in Bethlehem). Shepherds from the fields surrounding Bethlehem were told of the birth by an angel, and were the first to see the child.
耶稣具体的出生时间已被认定为九月份与十月份之间。现在所庆祝的圣诞节（12月25日）来源于公元后400余年，当基督教成为罗马王国的国教后，为了将当 时大众所庆祝的太阳之节（12月25日）与新的国教结合起来，之所以把耶稣的出生日定为现在圣诞节的日期。历史上耶稣的存在是历史学家们公认的（请参考有 关调查），但耶稣的神性却一直在辩论中。基督徒们相信耶稣同时是百分之百的人与百分之百的神，某些其它宗教相信耶稣是神的先知，或者是一位伟大的教师。 readmore »»
