The New York Islanders (colloquially known as the Isles) are a professional ice hockey team based in Elmont, New York. The Islanders compete in the National Hockey League (NHL) as a member of the Metropolitan Division in the Eastern Conference, and play their home games at UBS Arena. The Islanders are one of three NHL franchises in the New York metropolitan area, along with the New Jersey Devils and New York Rangers, and their fanbase resides primarily on Long Island.

The team was founded in 1972 as part of the NHL's maneuvers to keep a team from rival league World Hockey Association (WHA) out of the newly built Nassau Veterans Memorial Coliseum in suburban Uniondale, New York. After two years of building up the team's roster, they found almost instant success by securing 14 straight playoff berths starting with their third season. The Islanders won four consecutive Stanley Cup championships between 1980 and 1983, the seventh of eight dynasties recognized by the NHL in its history. Their 19 consecutive playoff series wins between 1980 and 1984 is a feat that remains unparalleled in the history of professional sports. They are the last team in any major professional North American sport to win four consecutive championships, and to date the last NHL team to win more than two consecutive Stanley Cup championships.

Following the team's dynasty era, the franchise ran into problems with money, ownership and management, an aging arena, and low attendance. Their woes were reflected on the ice, as the team has not won a division title since 1987–88, and went 22 seasons without winning a playoff series prior to the 2016 playoffs. After years of failed attempts to rebuild or replace Nassau Coliseum in suburban Long Island, the Islanders relocated to Barclays Center in Brooklyn following the 2014–15 season. In the 2018–19 and 2019–20 seasons, the Islanders split their home games between Barclays Center and Nassau Coliseum. The Islanders played all their home games in the 2020–21 season at Nassau Coliseum. Their new arena near Belmont Park was opened in 2021.

Nine former members of the Islanders have been inducted into the Hockey Hall of Fame, seven of whom—Mike Bossy, Clark Gillies, Denis Potvin, Billy Smith, Bryan Trottier, coach Al Arbour, and general manager Bill Torrey—were members of all four Cup-winning teams. Post-dynasty players Pat LaFontaine and Roberto Luongo were also inducted.