Balak was a king of Moab described in the Book of Numbers in the Hebrew Bible, where his dealings with the prophet Balaam are recounted. Balak tried to engage Balaam for the purpose of cursing the migrating Israelite community. On his journey to meet the princes of Moab, Balaam is stopped by an angel of the lord after beating his donkey. He tells the angel he will return home: "I have sinned, for I did not know that you stood against me on the road". The angel instructs Balaam to attend the meeting with the princes of Moab but to "say only what I tell you". According to Numbers 22:2, and Joshua 24:9, Balak was the son of Zippor.

The Book of Numbers is the fourth book of the Hebrew Bible and the fourth of five books of the Jewish Torah. The book has a long and complex history; its final form is possibly due to a Priestly redaction of a Yahwistic source made sometime in the early Persian period. The name of the book comes from the two censuses taken of the Israelites.