The 1973 New York Mets season was the 12th regular season for the Mets, who played home games at Shea Stadium. Manager Yogi Berra led the team to a National League East title with an 82–79 record and the National League pennant, though they were defeated by the Oakland Athletics in the World Series. Their .509 winning percentage is the lowest of any pennant-winner in major league history. Having won only 82 games during the regular season, they, along with the 2005 San Diego Padres, qualified for the postseason with the fewest regular season wins since Major League Baseball expanded to a 162-game season in 1961, and the fewest of any team since 1885. The season was well known for pitcher Tug McGraw's catchphrase "Ya Gotta Believe!!!"

The New York Mets are an American professional baseball team based in the New York City borough of Queens. The Mets compete in Major League Baseball (MLB) as a member of the National League (NL) East Division. They are one of two major league clubs based in New York City, the other being the American League's (AL) New York Yankees. One of baseball's first expansion teams, the Mets were founded in 1962 to replace New York's departed NL teams, the Brooklyn Dodgers and the New York Giants. The team's colors evoke the blue of the Dodgers and the orange of the Giants.