A people before the Ammonites
The main reference to the Zamzummim comes as Moses recounts Israel's journey toward Canaan. He explains that the land later occupied by the children of Ammon had once belonged to another people. The Ammonites called them Zamzummim, while other groups may have used different names for them (Deuteronomy 2:20).
That detail matters because Moses is showing that the Lord had assigned lands not only to Israel, but also to some of Israel's neighbouring peoples. Israel was therefore told not to seize Ammon's territory, since God had given it to Lot's descendants (Deuteronomy 2:19).
(That also was accounted a land of giants: giants dwelt therein in old time; and the Ammonites call them Zamzummims;
Strong, but not beyond God
Moses describes the Zamzummim as a great people, many in number, and tall in stature. He compares them with the Anakim, the well-known giant-like inhabitants whom Israel feared after the spies' report (Deuteronomy 2:21; Numbers 13:33).
Yet their strength was not the final word. Deuteronomy says that the Lord destroyed the Zamzummim before the Ammonites, who then lived in their place (Deuteronomy 2:21). The point is not to satisfy every historical curiosity. It is to remind Israel that the God who governs nations could also give Israel the land he had promised.
A people great, and many, and tall, as the Anakims; but the Lord destroyed them before them; and they succeeded them, and dwelt in their stead:
Are they the same as the Zuzims?
Some readers connect the Zamzummim with the Zuzims mentioned in the account of Chedorlaomer's campaign in Genesis 14:5. The names sound related, and both appear in the region east of the Jordan. It is a reasonable possibility, but Scripture does not explicitly say they were the same people.
So it is best to hold that connection lightly. Ancient peoples could be known by more than one name, especially when different communities spoke different languages. What the Bible states clearly is enough: the Zamzummim were a powerful earlier population of Ammon's land, and they were displaced before the Ammonites arrived.
Why their brief story is included
This small reference sits inside a larger lesson about God's faithfulness and justice. Israel was approaching nations that looked intimidating, but Moses repeatedly pointed to what God had already done among the peoples of the region. No nation's size, history, or military reputation placed it outside his rule.
It also encourages careful reading. Even unfamiliar names in Scripture belong to the real setting of God's story with his people. When a passage raises questions we cannot fully answer, we can still receive the truth it makes plain and keep reading with humility.