Hamilton Fish IV or Hamilton Fish Jr. was an American Republican politician who represented parts of New York's Hudson Valley region in the United States House of Representatives for thirteen terms from 1969 to 1995. Fish was a member of the prominent Fish political family; his grandfather and father, both also named Hamilton, represented the region from 1909 to 1911 and 1920 to 1945, respectively.

The Fish family is a prominent American family, members of which became influential in politics, diplomacy, and business. The family is of English origin and is descended from Jonathan Fish (1615–1663), who was born in East Farndon, Northamptonshire, England, and ultimately settled in the Province of New York.