Walter Henry Ruether (born in Alameda, California; September 29, 1893 – May 16, 1970) was an American baseball player who pitched for five different Major League teams. In his 11-year career, Ruether played for the Chicago Cubs, the Cincinnati Reds, the Brooklyn Robins, the Washington Senators, and the New York Yankees.
He appeared in the 1919 World Series with the Reds, in the 1925 World Series with the Senators, and in the 1926 World Series with the Yankees. Ruether was also a member of the 1927 Yankees. Though that team played in the 1927 World Series, Ruether did not participate in any of the games.