Charles Sinclair Weeks (June 15 1893 - February 7 1972), better known as Sinclair Weeks, was United States Secretary of Commerce from January 21, 1953 to November 10, 1958 under Dwight Eisenhower. He was also the mayor of Newton, Massachusetts from 1930 to 1935 and a United States senator from Massachusetts from February 1944 when he was appointed by the governor following the resignation of Henry Cabot Lodge, Jr., who went to serve in World War II, until December 1944, when a new senator was elected. Weeks did not run in that election.

Weeks graduated from Harvard University, served on the Mexican border with the National Guard in 1916, and served in World War I. He was a businessman in various industries for much of his adult life, before, after and druing his political activity. Weeks was a member of the United States Republican Party. He served as a member of the Republican National Committee from 1941 to 1953 and served as treasurer of the party from 1940 to 1944.

Weeks' father, John W. Weeks (1860-1926), was a United States congressman and senator from Massachusetts and the United States Secretary of War from 1921 to 1925.