Harry "Socks" Seibold (May 31, 1896 – September 21, 1965) was an American professional baseball pitcher.

He played in Major League Baseball (MLB) for the Philadelphia Athletics and Boston Braves.

He played parts of 1916, 1917, and 1919 for the Athletics, and then spent the next nine years out of the major leagues.

For four seasons, he was a regular in the Braves' rotation, and in 1930 set his career high in innings pitched with 250, wins with 15 and strikeouts with 70.

This biographical article relating to an American baseball pitcher born in the 1890s is a stub.