Shem is named first in the Genesis list of Noah’s sons.
Genesis 5:32 and 6:10 list Noah’s sons as Shem, Ham, and Japheth. Genesis later repeats the sequence when describing the family members who survived the Flood aboard the Ark.
The first position does not by itself settle every question about birth order. Genesis 10:21 uses wording that has led translators and commentators to debate whether Japheth or Shem was older. For that reason, a question about the first name in the list is more precise than a question asking for the eldest son.
Shem becomes especially important in the genealogy that follows the Flood. Genesis traces a line from Shem through later generations to Abram, who is introduced in the next major genealogical section. Ham and Japheth also receive descendants and nations in the biblical account.