After The Flood, the Hittites originated from Noah's great-grandson Heth, through Ham and Canaan:

"the sons of Noah: Shem, Ham, and Japheth ... the sons of Ham: Cush, Egypt, Put, and Canaan ... Canaan became the father of Sidon his first-born, and Heth" (Genesis 10:1,6,15 RSV)

After Sarah died, it was from the Hittites that Abraham bought the cave in Hebron, known today as the "Tomb of the Patriarchs," in which Abraham, Sarah, Isaac, Rebekah, Jacob/Israel and Leah are all buried:

"Abraham buried Sarah his wife in the cave of the field of Machpelah east of Mamre, that is, Hebron, in the land of Canaan. The field and the cave that is in it were made over to Abraham as a possession for a burying place by the Hittites (KJV the sons of Heth)." (Genesis 23:19-20 RSV)

Two of the wives of Esau were Hittites:

"When Esau was forty years old, he took to wife Judith the daughter of Beeri the Hittite, and Basemath the daughter of Elon the Hittite; and they made life bitter for Isaac and Rebekah." (Genesis 26:34-35 RSV)

Upon their entry into the Promised Land under Joshua, the Israelites were commanded by God to displace the inhabitants of the land, which included Hittites:

And Joshua said, "Hereby you shall know that the living God is among you, and that He will without fail drive out from before you the Canaanites, the Hittites, the Hivites, the Perizzites, the Girgashites, the Amorites, and the Jebusites." (Joshua 3:10 RSV)

The incident of adultery with Bathsheba, the wife of Uriah the Hittite, and Uriah's murder to cover it up, was one of the greatest personal failures of King David:

"Why have you despised the word of The Lord, to do what is evil in His sight? You have smitten Uriah the Hittite with the sword, and have taken his wife to be your wife, and have slain him with the sword of the Ammonites." (2 Samuel 12:9 RSV)

Fact Finder: Did King Solomon include Hittite women among his many wives?
1 Kings 11:1