Gerar (Hebrew: גְּרָר Gərār, "lodging-place") was a Philistine town and district in what is today south central Israel, mentioned in the Book of Genesis and in the Second Book of Chronicles of the Hebrew Bible.

According to the International Standard Bible Encyclopedia, the biblical valley of Gerar (Genesis 26:17) was probably located in the area of a valley known in Arabic as Wady Sheri'a, and in Modern Hebrew as Nahal Gerar. Most commentators see the mound of Tel Haror (Hebrew) or Tell Abu Hureyra (Arabic) as representing the ancient Gerar.

Some older commentaries, such as Smith's Bible Dictionary, stated simply that Gerar was located "south of Gaza". Also, a ninth century rabbinical source, Saadia Gaon, identified Gerar with Haluza, which is located along the Besor Stream in the Negev. However, according to recent archaeological research, Haluza only dates to the period of the Nabataean Kingdom.

Biblically, the town features in two of the three wife-sister narratives in Genesis. These record that Abraham and Isaac each stayed at Gerar, near what became Beersheba, and that each passed his wife off as his sister, leading to complications involving Gerar's Philistine king, Abimelech. (Genesis 20:1, and Genesis 26:1)

The Haggadah identifies the two references to Abimelech as two separate people, the second being the first Abimelech's son, and that his original name was Benmelech ["son of the King"], but he changed his name to his father's, meaning "my father is king".

In 2 Chronicles 14:12-15, Gerar and its surrounding towns figure in the account of King Asa's defeat of Zerah's vast Cushite forces.

• Tell Jemmeh

31°22′54″N 34°36′25″E / 31.3817°N 34.6069°E / 31.3817; 34.6069