2017 Major League Baseball postseason

The 2017 Major League Baseball postseason was the playoff tournament of Major League Baseball for the 2017 season. The winners of the Division Series would move on to the League Championship Series to determine the pennant winners that face each other in the World Series. This was the first edition of the postseason in which home field advantage in the World Series was awarded to the team with the better regular season record, rather than the winner of the Major League Baseball All-Star Game.

In the American League, the Cleveland Indians and Boston Red Sox returned for the second year in a row, the Houston Astros and New York Yankees returned for the second time in three years, and the Minnesota Twins made their first appearance since 2010. This was the first of what is currently eight consecutive postseason appearances for the Astros. It was also the first of six consecutive appearances for the Yankees.

In the National League, the Washington Nationals returned for the fourth time in six years, the Los Angeles Dodgers made their fifth straight appearance, the Chicago Cubs made their third straight appearance, the Arizona Diamondbacks made their first appearance since 2011, and the Colorado Rockies returned for the first time since 2009. This was the first postseason since 2003 to feature three 100-win teams.

The postseason began on October 3, and ended on November 1, with the Astros defeating the Dodgers in seven games in the 2017 World Series. It was the Astros' first title in franchise history.