William Stephens Smith (November 8, 1755 – June 10, 1816) was a United States Representative from New York. He married Abigail "Nabby" Adams, the daughter of President John Adams, and so was a brother-in-law of President John Quincy Adams, and an uncle of Charles Francis Adams. Born on Long Island, he graduated from the College of New Jersey (now Princeton University) in 1774, and studied law for a short time.