How many wives did Esau have? He first had two Hittite wives, Basemath, the daughter of Elon, and Judith, the daughter of Beeri, as recorded in Genesis 26:34-35. Then the sister of Nebaioth, Ishmael’s daughter Mahalath (Gen 28:8-9). However, later in Gen 36:2-3, it is stated that his wives are Adah, the daughter of Elon, Bashemath, the daughter of Ishmael, and Aholibamah, the daughter of Anah, the daughter of Zibeon, the Hivite. Esau’s children were Eliphaz (from Adah), Reuel (from Bashemath), and Jeush, Jaalam, and Korah (all three from Aholibamah).

He either had six wives or four 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). Then, Aholibamah, his last wife. Judith didn’t have any sons and therefore is not listed in the genealogy records in Gen 36. In genealogical lists, such as in Gen 36, typically only male heirs are listed, and women are only listed as a rare exception, usually to highlight a specific point. If the wives only had daughters or were barren, they would not have been mentioned here.

If he had six 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. He married his last wife, Aholibamah, who was among the native inhabitants of Mt. Seir listed in Genesis 36:20-25.

If there was a name change, then Judith and Aholibamah are the two wives whose names are consistent, and the other four 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

Some have suggested Aholibamah may have possibly been an incestuous daughter of Zibeon the Hivite, since the text says “daughter of Anah, daughter of Zibeon” in verse 2 (KJV), but that is not the only option; it could be that the word daughter was used in a way that meant descendant (granddaughter).

According to the medieval French Jewish scholar and commentator Rashi (also known as Jarchi), there was a name change for Basemath, the daughter of Elon, and Mahalath, the daughter of Ishmael. He suggests that Adah was just another name for Bashemath. Adah means “ornament” and Bashemath means “fragrance”, “perfume”, or “spice”.  He suggests that 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 to pardon his sins. Remember, Esau married her to appease his parents, who were not happy with his first two wives. He has also noted Judith being matched with Aholibamah. Still, 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 [Isaac].” 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 also had correspondence with the apologetics ministry Answers in Genesis regarding this topic, and they stated that both options are possible. 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 had died, or because Basemath (now renamed Adah) had given birth to 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 have a leaning towards one or the other; I guess it depends on whether 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 Seir, which is the land that Esau’s descendants eventually conquered and called Edom.

Resources:
A Look at Yarchi’s Commentary
Various Commentaries on bible hub with their own insights