How many wives did Esau have? He first had 2 Hittite wives, Basemath daughter of Elon, and Judith daughter of Beeri in Gen 26:34–35. Then the sister of Nebaioth, Ishmael’s daughter Mahalath (Gen 28:8-9). But then later it says in Gen 36:2-3 that his wives are Adah the daughter of Elon, Bashemath the daughter of Ishmael, and Aholibamah the daughter of Anah, the son of Zibeon the Hivite. Esau’s children were Eliphaz (from Adah), Reuel (from Bashemath), and Jeush, Jaalam, and Korah (all 3 from Aholibamah).
It seems like he either had 6 wives or 4 wives. In the six-wife scenario, three of them were barren, or only had girls. These three are Judith daughter of Beeri, Basemath daughter of Elon, and Mahalath the daughter of Ishmael. Meanwhile, the latter three (Adah, Bashmemath, and Aholibamah) gave him sons.
Alternatively, he had 4 four wives, and two of them had name changes. Those two are Basemath to Adah (daughter of Elon) and Mahalath to Bashemath (daughter of Ishmael). Aholibamah was his last wife, and has a different father from the others and is a Hivite from Mt. Sier, not a Hittite. Judith didn’t have any sons and therefore is not listed in the genealogy records in Gen 36. In genealogy list like in Gen 36, typically only male heirs are listed, and women are only listed as a rare exception, usually to point out something. So if the wives only had daughters they would not have been mentioned here.
If he had 6 wives, the first three Judith, Basemath, and Mahalath didn’t give him any sons, so he married Basemath’s sister Adah, and Mahalath’s sister Bashemath. Then he got a final wife named Aholibamah from Anah, the son of Zibeon the Hivite, who was among the native inhabitants of Mt. Sier listed in Genesis 36:20-25.
If there was a name change then Judith and Aholibamah are two wives and the other 4 names represent two sets of people each with a name change:
Basemath = Adah, the daughter of Elon the Hittite;
Mahalath = Bashemath the daughter of Ishmael, sister of Nebaioth
Aholibimah may have possibly been an incestuous daughter of Zibeon the Hivite since the text says “daughter of Anah, daughter of Zibeon” in verse 2, but that is not the only option, it could be the word daughter was used in a way that meant descendant (granddaughter).
It is suggested by the medieval French Jewish scholar and commenter Rashi (Jarchi), that there was a name change for Basemath daughter of Elon, and Mahalath daughter of Ishmael. He suggests that Adah was just another name for Bashemath. Adah means “ornament” and Bashemath means “fragrance”, “perfume” or “spice”. His suggestion is she was called this because she offered spices (בשמים) as incense to idols. He says that the daughter of Ishmael Basemath was called Mahalath as a reference to a “pardon”. The idea is that Esau married her in order to pardon his sins. Remember Esau married her to appease his parents who were not happy with his first two wives. He also has noted Judith being matched with Aholibamah but I don’t think they are the same person unless her dad changed his name from Berri to Anah, He says, “he (Esau) changed her name to Judith (Jewess), suggesting that she had abandoned idol-worship so that he might deceive his father.” He further mentions that Aholibamah was born from incest because her grandfather Zibeon is also her father and must have conceived her with his son’s wife.
I had a correspondence with the apologetics ministry Answers in Genesis about this topic as well and they said that both options are possible and they had some ideas for the name change theory based on Jarchi’s work. They said: “Bashemath could have been named ‘fragrance’ by her father but was changed from second wife status to ‘ornament’ by Esau. Esau may have done this because Judith died or because Basemath (now renamed Adah), had the firstborn son Eliphaz. Mahalath (named by her father “melodious tune”) was probably renamed ‘perfume’ or ‘spice’ because she was now the youngest wife, and probably the more ardent lover of Esau’s wives.”
I don’t really have a leaning towards one or the other, I guess it really depends on if their names were changed or not. We know for sure that three wives gave him his sons and Aholibamah was his final wife from one of the elders of the land of Sier which is the land that Esau’s descendants eventually conquer and call Edom.
A Look at Yarchi’s Commentary