The 1985 National League Championship Series was played between the St. Louis Cardinals and Los Angeles Dodgers from October 9–16. It was the 17th NLCS and the first played under the new best-of-seven format. In previous years, the NLCS had been settled by a best-of-five format. This series is best known for Ozzie Smith's dramatic walk-off home run in Game 5. This is the second consecutive NLCS where a team overcame a 2–0 series deficit to win the series after the Padres did so in the best-of-five 1984 NLCS.

The National League Championship Series (NLCS), also known as the National League Pennant, is a best-of-seven playoff and one of two League Championship Series comprising the penultimate round of Major League Baseball's (MLB) postseason. It is contested by the winners of the two National League (NL) Division Series. The winner of the NLCS wins the NL pennant and advances to the World Series, MLB's championship series, to play the winner of the American League's (AL) Championship Series. The NLCS began in 1969 as a best-of-five playoff and used this format until 1985, when it changed to a best-of-seven format.