Deir Yassin (Arabic: دير ياسين, romanized: Dayr Yāsīn) was a Palestinian Arab village of around 600 inhabitants about 5 kilometers (3.1 mi) west of Jerusalem. Deir Yassin declared its neutrality during the 1948 Palestine war between Arabs and Jews. The village was razed after a massacre of around 107 of its Arab residents on April 9, 1948, by the Jewish paramilitary groups Irgun and Lehi. The village buildings are today part of the Kfar Shaul Mental Health Center, an Israeli public psychiatric hospital.

The first part of the village's name Deir is defined as "monastery" in Arabic. According to Palestinian historian Walid Khalidi, this was a common occurrence in Palestinian village names especially those so close to Jerusalem. A large ruin that lay at the southwestern edge of Deir Yassin was known simply as "Deir".

Deir Yassin has been identified as one of the villages given as a fief to the Church of the Holy Sepulchre in the 12th century. However, in 1136 Fulk, King of Jerusalem confirmed it was a casale under the Knights Hospitallers. It has been suggested that a vaulted building in the center of the village could have been of Crusader or Mamluk origin.

Tawfiq Canaan noted that a yellow stone, popular in the Jerusalem Mamluk ablaq building decorations, was apparently quarried at Deir Yassin towards the end of the fifteenth century.

During the Ottoman era, which began in 1517, the nucleus of settlement activity in the area was Khirbet Ayn al-Tut ("The Ruin of the Mulberry Spring")—some 500 meters (1,600 ft) west of the 1948 village site. In 1596, this village was under the administration of the nahiya (subdistrict) of Jerusalem, part of the sanjak (district) of Jerusalem. It had a population of seven Muslim households, who paid taxes on wheat, barley, and olive trees; a total of 4,522 akçe. All of the revenue went to a waqf.

It is unknown precisely when settlement shifted to Deir Yassin. The village was named in honor of a certain Sheikh Yassin whose tomb was in a mosque, or shrine located just outside the village, on a high spot, dominating the surrounding area. The village guesthouse, or Madafeh, was located opposite the shrine.

Edward Robinson noted the village in 1838, and by 1870, an Ottoman village list indicated 13 houses and a population of 48, though the list only counted men. In 1896 the population of Deir Yassin was estimated to be about 138 persons.

In the late 19th century, the houses of Deir Yassin were built of stone. Two springs—one located in the north and another in the south—supplied water to the village. Most of its houses, strongly built with thick walls, were clustered in a small area known as the Hara meaning "Quarter" or "Neighborhood". All residents were Muslims. In 1906, a Jewish suburb of Jerusalem, Givat Shaul, was built across the valley from Deir Yassin. The secondary road linking the village to Jerusalem and the road to Jaffa ran through the suburb.