The Christian Quarter (Arabic: حارة النصارى, romanized: Ḥāraṫ al-Naṣārā; Hebrew: הרובע הנוצרי, romanized: Ha-Rova ha-Notsri) is one of the four quarters of the walled Old City of Jerusalem, the other three being the Jewish Quarter, the Muslim Quarter and the Armenian Quarter. The Christian Quarter is situated in the northwestern corner of the Old City, extending from the New Gate in the north, along the western wall of the Old City as far as the Jaffa Gate, along the Jaffa Gate – Western Wall route in the south, bordering on the Jewish and Armenian Quarters, as far as the Damascus Gate in the east, where it borders on the Muslim Quarter.

The Christian quarter contains about 40 Christian holy places and one of the most important communities of Christianity in there and holy places for Christians in the world. First among them is the Church of the Holy Sepulchre, Christianity's holiest place. Most of the residents of the Christian quarter remain Christians however their numbers have dwindled.

The Christian Quarter was built around the Church of the Holy Sepulchre, which is the heart of the quarter, and Christian churches and institutions are spread across much of the quarter. Besides the Church of the Holy Sepulchre, there are the patriarchal seats of many Christian denominations, including the Greek Orthodox Patriarchate of Jerusalem, which owns large tracts of the quarter, the Latin Patriarch of Jerusalem, the Greek Catholic Patriarchate of Jerusalem, the Coptic Patriarchate of Jerusalem and the Ethiopian Patriarchate of Jerusalem, while the Franciscan Monastery of St Saviour (often called by its Italian name, San Salvatore) is the seat of the Custody of the Holy Land.

The west–east David Street and north–south Christian Quarter Road, or simply Christian Road, are the principal market streets. Several hotels, including the Casa Nova Hotel and the Greek Catholic hotel, were built by the churches as places for religious visitors and pilgrims to stay. The quarter also contains museums, including one about the Greek Orthodox Patriarchate. In the southwestern part of the quarter there is a pool called Hezekiah's Pool or Patriarch's Pool that was traditionally used to store water for the area.

The area originated as "Haret en-Nasara" (Nasara is cognate with "Nazarenes") in the middle of the area was later to become the "Christian Quarter". The convention of the boundaries of the Christian Quarter have originated in its current form in the 1841 British Royal Engineers map of Jerusalem, or at least Reverend George Williams' subsequent labelling of it. The city had previously been divided into many more harat (Arabic: حارَة, romanized: Hārat: "quarters", "neighborhoods", "districts" or "areas").

The table below shows the evolution of the area which was to become known as the Christian Quarter, from 1495 up until the modern system:

During the 4th century, Emperor Constantine's mother, Helena, journeyed to the Holy Land, aiming to engage in acts of charity and establish churches, particularly in locations associated with significant events in the life of Jesus Christ. During this period, a prominent narrative emerged about Helena's discovery of the cross. This legend, widely recognized in Late Antiquity, is detailed in Jacopo de Varazze's 13th-century Legenda Aurea, which not only recounts the myth surrounding the cross but also commends Helena as an exemplary Christian within the Catholic Church.

According to the legend, while en route to Jerusalem, Helena encountered three crosses, one of which was believed to be the cross of Christ, accompanied by the purported nails. The narrative describes three ailing individuals approaching the crosses, with the third person experiencing a miraculous healing upon touching the cross of Christ. The designated site of this discovery is said to be where the Basilica of the Holy Sepulchre was subsequently erected. Helena is also credited with the establishment of the Church of the Nativity. The cross of Christ and other relics linked to this discovery became subjects of subsequent controversies within the church.