1978 Major League Baseball postseason

• New York Yankees – AL East champions, 100–63 (on tiebreaker)[2]
• Kansas City Royals – AL West champions, 92–70[3]

• Philadelphia Phillies – NL East champions, 90–72[4]
• Los Angeles Dodgers – NL West champions, 95–67[5]

New York won the series, 3–1.

For the third year in a row, the Yankees and Royals met in the ALCS, and once again the Yankees came out on top, this time in four games, to return to the World Series for the third year in a row. In Kansas City, the Yankees blew out the Royals in Game 1, while in Game 2, the Royals responded with a blowout victory of their own to even the series. Game 3 was a slugfest that the Yankees narrowly won, thanks to a two-run home run from Thurman Munson in the bottom of the eighth. Game 4 was a pitchers' duel between Yankees' ace Ron Guidry and Royals' ace Dennis Leonard, which would be won by the former as the Yankees narrowly prevailed by one run to secure the pennant.

Both teams would meet once more in the 1980 ALCS, where the Royals finally broke through. The Yankees would win their next AL pennant in 1981 over the Oakland Athletics in a sweep.

Los Angeles won the series, 3–1.

For the second consecutive year, the Dodgers and Phillies met in the NLCS. The Dodgers yet again prevailed in four games and advanced to the World Series for the second straight year.

The Dodgers stole a Game 1 slugfest on the road, 9–5. They then took Game 2 off a complete-game shutout from ace Tommy John. When the series shifted to Los Angeles for Game 3, the Phillies jumped out to an early lead and did not relinquish it, as they won by a 9–4 score to avoid a sweep. However, the Dodgers ended up winning the pennant in Game 4 with a narrow victory in extra innings.

The two teams would meet in the NLCS again in 1983, 2008 and 2009, however all three would be won by the Phillies. The Phillies would return to the NLCS in 1980, where they defeated the Houston Astros in five games to return to the World Series and win their first ever championship. The Dodgers would win their next NL pennant in 1981 over the Montreal Expos in five games.

New York won the series, 4-2.

This was the tenth World Series meeting in the history of the Dodgers-Yankees rivalry. In a near identical outcome to last year's series, the Yankees overcame a two games to none series deficit to again defeat the Dodgers in six games, repeating as World Series champions.

In Los Angeles, the Dodgers blew out the Yankees in Game 1, and overcame a late Yankees' lead in Game 2 thanks to a three-run home run from Ron Cey. When the series shifted to the Bronx, the Yankees got on the board in Game 3 off a complete-game performance from ace Ron Guidry. In Game 4, the Yankees evened the series in extra innings as Lou Piniella drove in Roy White with an RBI single in the bottom of the tenth. Jim Beattie unexpectedly pitched a complete game in Game 5 as the Yankees blew out the Dodgers by ten runs to take a 3–2 series lead headed back to Los Angeles. In Game 6, Catfish Hunter helped lead the Yankees to victory, as they repeated as World Series champions.

Game 6 of the 1978 World Series was the last for Yankees catcher Thurman Munson, who died in a plane crash on August 2, 1979, at Akron-Canton Airport in Ohio.[21][22][23]

These historical rivals would meet each other once more in the 1981 World Series, and in that series the Dodgers would prevail. This was the last time the Yankees won the World Series until 1996, where they defeated the Atlanta Braves in six games to end an 18-year championship drought.