Noah’s youngest son in the Genesis account was Ham.
Genesis names Noah’s three sons as Shem, Ham, and Japheth. In the account of Noah’s drunkenness after the flood, Ham is identified as the father of Canaan. Genesis 9 describes an incident involving Noah’s uncovered state and the differing reactions of his sons, after which Noah pronounces a curse on Canaan rather than directly naming Ham as cursed.
The three sons are important because the narrative presents them as ancestors of peoples and nations known to the biblical authors. Later chapters develop genealogical lists associated with Shem, Ham, and Japheth, though those lists should not be treated as modern population science or a complete historical map of humanity.
Some readers assume the sons are listed in birth order, but Genesis does not make every detail of their relative ages equally explicit. The specific identification of Ham as the youngest appears in Genesis 9:24. This question therefore depends on the wording of that passage, not merely on the common ordering of the names.