William Lawrence Saltonstall (May 14, 1927 – January 23, 2009), an American politician, was a member of the Massachusetts Senate from 1967 to 1979. He was a Republican and a resident of Manchester-by-the-Sea, Massachusetts. He led an unsuccessful campaign in 1969 to represent Massachusetts's 6th congressional district in the U.S. House of Representatives.
Born in Chestnut Hill, Massachusetts, he was a member of the Saltonstall family, which had strong historical roots in Massachusetts. His father, Leverett Saltonstall (1892–1979), was a Massachusetts governor and a U.S. senator. While the Saltonstall men were known to join the U.S. Army, he instead enlisted the U.S. Navy on his eighteenth birthday. His first day of service was V-J Day in 1945. With World War II at its end, Saltonstall enrolled at Harvard College, from which he graduated in 1949. He later graduated from Harvard Business School.
After working as a security analyst for seven years, Saltonstall worked at his father's U.S. Senate office in Washington, D.C. He returned to Massachusetts in 1966 where he ran for the state Senate. He won, and went on to represent the Third Essex district from 1967 to 1975 and the First Essex and Middlesex district from 1975 to 1979. One of his top priorities was bicycle safety. Saltonstall ran for the U.S. House in a 1969 special election to succeed the deceased William H. Bates from the 6th Massachusetts district, but lost to Democrat Michael J. Harrington.
Saltonstall married Jane Chandler in 1953. They had three children, Abigail, Claire, and William, Jr. Claire was struck and killed by an automobile driver in 1974 while she was riding her bicycle. The Claire Saltonstall Bikeway from Boston's Emerald Necklace to Provincetown is named in her memory.
On a Friday evening in January 2009, after returning home from dinner with his wife, Saltonstall died "of an apparent heart attack or blood clot".