Tom Herr (born 1956 in Lancaster, Pennsylvania) is a former second baseman in Major League Baseball who played from 1979 to 1991 for the St. Louis Cardinals, Minnesota Twins, Philadelphia Phillies, San Francisco Giants, and New York Mets. Herr played in the 1982, 1985, and 1987 World Series - all with Cardinals, finishing fifth in the MVP voting and making his only appearance in the All-Star Game.
Early in the 1988 season he was traded to the Twins for Tom Brunansky.
In a 13-season career, he batted .271 with 28 home runs and 574 RBIs in 1514 games. He had 1450 career hits in 5349 at bats. He is best remembered for hitting a walk-off grand slam in extra innings against the New York Mets on April 18, 1987, on Seat Cushion Night at Busch Stadium.
His son Aaron Herr was drafted by the Atlanta Braves in the first round during the 2001 season. The younger Herr played the 2005 season with the Springfield Cardinals, the AA farm team of the St. Louis Cardinals.
Herr was hired in November 2004 as the first manager of his hometown Lancaster Barnstormers, a team in the independent Atlantic League of Professional Baseball.