Bayt Mahsir (Arabic: بيت محسير) was a Palestinian Arab village in the Jerusalem Subdistrict. It was depopulated during the Nakba on May, 1948 by the Harel Brigade in Operation Makkabi. It was located 9 km west of Jerusalem.

In 1945, the village had a population of 2,400. Bayt Mahsir had three schools; two schools for boys and an elementary school for girls. Bayt Mahsir contains a number of khirbat, including al-Huwaytiyya, al-Masi, Khatula and al-Sallam.

According to the Palestinian historian Walid Khalidi, the village remaining structures on the village land are: "Several village houses have been spared, and are for the most part interspersed among the houses of the settlement of Beit Meir. Two large, rectangular-shaped, almost identical houses built of limestone rise above the Israeli settlement's cabin-like residences. The remains of a flour mill, a metal machine with flywheels fitted over a stone structure, can still be seen. There is a wild forest of old trees on the eastern edge of the village site, on top of the mountain. The tomb of al-' Ajami, together with other graves, are among the trees." Source