Joseph Aloysius Ruddy Sr. (September 28, 1878 – November 11, 1962) was an American competition swimmer and water polo player who represented the United States at the 1904 Summer Olympics in St. Louis, Missouri. Ruddy won a gold medal as a member of the winning U.S. team in the men's 4x50-yard freestyle relay. He won a second gold medal as a member of the first-place U.S. water polo team. Ruddy was the father of 1928 Olympic swimmer Ray Ruddy, and two other sons and two daughters. His oldest son and namesake, Joseph Ruddy, Jr. was a U.S. Navy admiral. He died at his home in Far Rockaway, New York in 1962 at the age of 84. In 1977, he was inducted into the USA Water Polo Hall of Fame.