Genesis 25:16

these are sons of Ishmael, and these their names, by their villages, and by their towers; twelve princes according to their peoples.

Genesis 17:20

As to Ishmael, I have heard thee; lo, I have blessed him, and made him fruitful, and multiplied him, very exceedingly; twelve princes doth he beget, and I have made him become a great nation;

Genesis 17:23

And Abraham taketh Ishmael his son, and all those born in his house, and all those bought with his money -- every male among the men of Abraham's house -- and circumciseth the flesh of their foreskin, in this self-same day, as God hath spoken with him.

Treasury of Scripture Knowledge

Summary

These are the sons of Ishmael, and these are their names, by their towns, and by their castles; twelve princes according to their nations.

Twelve

Bible References

Twelve

Genesis 17:20
As to Ishmael, I have heard thee; lo, I have blessed him, and made him fruitful, and multiplied him, very exceedingly; twelve princes doth he beget, and I have made him become a great nation;