The 1998 Big 12 Championship Game was played on December 5, 1998, at The Trans World Dome in St. Louis, Missouri, United States. The game determined the 1998 football champion of the Big 12 Conference. The Texas A&M Aggies, winners of the South Division of the Big 12, narrowly beat the Kansas State Wildcats, who won the North division, by a score of 36–33 in double overtime. This was the first time the two teams met in the Big 12 Championship Game. Texas A&M would not win the South Division again until the 2010 season, when they shared it with Oklahoma and Oklahoma State. Kansas State went on to win the North in 2000 and 2003, when they also beat Oklahoma to capture their first conference title since 1934.
The Wildcats were coached by Bill Snyder. They came into the game with an 11–0 record, including an 8–0 record in Big 12 play. The Aggies, coached by R. C. Slocum, went into the game with a 10–2 record including a 7–1 mark in conference play.