The 1984 American League Championship Series matched the East Division champion Detroit Tigers against the West Division champion Kansas City Royals. The Tigers took the series in a three-game sweep to advance to the 1984 World Series against the San Diego Padres. The series was the 16th ALCS in all and the last to be played as a best-of-five. In 1985, the League Championship Series changed to a best-of-seven format.