The primary and most fierce historical rival of the Philadelphia Phillies is the New York Mets, with their divisional battles in the National League East frequently characterized by intense competition, passionate fan clashes, and high-stakes regular-season series. Additionally, the Phillies share fierce historic rivalries with other National League powerhouses like the Atlanta Braves and the Washington Nationals, as well as an interleague cross-state rivalry with the Boston Red Sox or historical matchups against traditional opponents across the league.