Arba (ארבע) (meaning "four") was a man mentioned in assorted, but early, Old Testament verses of the Bible. In Joshua 14:15, he is cited as the "greatest man among the Anakites" and the father of Anak. Arba himself was the father of Anak, whose descendents went on to be called the Anakites, or "Anakim," which is the Hebrew plural. Arba himself was not an Anakite, since he was the progenitor.

The Anakites were said to have been a mixed race of giant people. Although the scriptures allude to their being Nephilim (again, Hebrew plural for Nephal), which were a crossbreed of fallen angels and humans, as cited in Genesis 6:1-2 and Genesis 6:4.

No early history of Arba is given in the Old Testament and little is known of his genealogy, with the exception of his child, Anak, and three possible grandsons, Sheshai, Ahiman, and Talmai, who were driven out of the land Caleb inherited, as cited in Joshua 15:13-14.

The Bible also mentions that the modern city of Hebron, in ancient times was know to be called Kirjath-arba or "Kiriath Arba" (city of Arba) after Arba. Although a modern day settlement exists east of Hebron named Kiryat Arba, its relation is not known.