The 1912 South Dakota gubernatorial election was held on November 5, 1912. Incumbent Republican Governor Robert S. Vessey declined to run for re-election to a third term. Lieutenant Governor Frank M. Byrne won the Republican primary to succeed Vessey, and then faced State Senator Edwin S. Johnson, the Democratic nominee, in the general election. Byrne only narrowly defeated Johnson, winning just 49% of the vote to Johnson's 46%, the closest gubernatorial election since 1898.
Primary elections were held on June 4, 1912.