Japheth is the son of Noah whose descendants are listed first in Genesis 10.
Genesis 10 is often called the Table of Nations. It begins with the descendants of Japheth, continues with the descendants of Ham, and ends with the descendants of Shem. The chapter presents a traditional map of peoples known to the biblical world, organized through Noah's three sons after the Flood.
The order of the genealogical sections is not the same as the usual theological importance assigned to the sons. Shem's line is presented last, but it leads into the genealogy of Abram in Genesis 11. Ham's section includes nations such as Egypt and Canaan, while Japheth's section names groups associated by many interpreters with regions around the Aegean and Anatolia.
Readers can easily confuse this question with the order in which the sons are named elsewhere. Genesis commonly lists Shem, Ham, and Japheth together. In the Table of Nations, however, Japheth's descendants appear first.