Thomas Erwin "Tom" McMillan, also known as "Tommy" McMillan, is a retired professional baseball player whose career spanned seven seasons, including one in Major League Baseball with the Seattle Mariners. As a member of the inaugural Mariners team, McMillan, a shortstop, went hitless in five at-bats. The majority of his career was spent in the minor leagues. After he was drafted out of Jacksonville University by the Cleveland Indians during the 1973 Major League Baseball Draft, McMillan made his professional debut that year with the Double-A San Antonio Brewers.
Over his minor league career, McMillan played with the Double-A San Antonio Brewers, Triple-A Oklahoma City 89ers, the Triple-A Toledo Mud Hens, the Triple-A Iowa Oaks, the Triple-A New Orleans Pelicans, the Triple-A Rochester Red Wings, the Triple-A San Jose Missions, and the Double-A Buffalo Bisons. In 711 minor league career games, McMillan batted .252 with 591 hits, 74 doubles, 24 triples, and 10 home runs.