Philip Aloysius Hart (December 10, 1912–December 26, 1976) was a Democratic senator from Michigan. He was nicknamed the Conscience of the Senate, which is also the name of a biography of Hart by Michael O'Brien.

He was born in Bryn Mawr, Pennsylvania and attended Waldron Academy and parochial schools. He graduated from Georgetown University in 1934 and from the University of Michigan Law School in 1937. He was admitted to the Michigan bar in 1938 and practiced law in Detroit, Michigan. During the Second World War, he served in the U.S. Army from 1941 until discharged in 1946 as a lieutenant colonel of Infantry. He was wounded during the D-Day assault on Utah Beach in Normandy, France.

After the war, he was the Michigan Corporation Securities Commissioner from 1949 until his resignation in 1951. He was the State director of the Office of Price Stablization, 1951-1952, and the U.S. Attorney for the Eastern District of Michigan, 1952-1953. He was legal advisor to the Governor of Michigan, 1953-1954, and lieutenant governor, 1955-1958.

He was elected as a Democrat to the U.S. Senate in 1958, and was reelected in 1964 and 1970. He did not run for reelection to a fourth term in 1976. Hart died of cancer in 1976, a few days before his term would have expired and he would have retired. Donald W. Riegle, Jr., who had just been elected as Senator, was named to fill Hart's seat for the remaining days of the congressional session.

The third of the Senate Office Buildings, Hart Senate Building, was officially dedicated and named for Senator Hart in 1987. The Hart-Dole-Inouye Federal Center in Battle Creek, Michigan also bears his name. He is interred in St. Anne’s Catholic Cemetery on Mackinac Island.