| New York Islanders | — | Brooklyn, Elmont, Uniondale | 1972 | UBS Arena, Barclays Center, Nassau Veterans Memorial Coliseum |
| New York Jets | National Football League | Nueva York, East Rutherford | 1960 | MetLife Stadium |
| New York Knicks | National Basketball Association | Nueva York | 1946 | Madison Square Garden, Madison Square Garden (1925), 69th Regiment Armory |
| New York Mets | Grandes Ligas de Béisbol | — | 1962 | Citi Field |
| New York Rangers | — | Manhattan | 1926 | Madison Square Garden (1925), Madison Square Garden |
| New York Yankees | Grandes Ligas de Béisbol | El Bronx | 1903 | Yankee Stadium, Yankee Stadium, Hilltop Park, Shea Stadium, Polo Grounds |
| Nordiques de Québec | — | — | 1972 | Colisée de Québec |
| Nova Virtus Ragusa | — | Ragusa | — | — |
| NPC Rieti | — | Rieti | 2011 | — |
| Nuova Fiamma Stabia | — | — | — | — |
| Nuova Pallacanestro Gorizia | — | Goricia | 1934 | — |
| Nuova Pallacanestro Vigevano | — | Vigevano | 1955 | — |
| Oakland Athletics | Grandes Ligas de Béisbol | Oakland | 1968 | Oakland Coliseum |
| OBG Roma | — | — | — | — |
| Oklahoma City Thunder | National Basketball Association | Oklahoma City | 2008 | Climate Pledge Arena, Tacoma Dome, Paycom Center, Kingdome |
| Oleggio Magic Basket | — | Oleggio | — | — |
| Olimpia Cagliari | — | Cagliari | 1953 | — |
| Olimpia Milano | Lega Basket Serie A | Milán | 1936 | Forum di Milano |
| Olympia 68 Basketball | — | Regio de Calabria | — | — |
| Olímpico Peruano | Copa Perú | — | 2 de febrero de 1945 | — |
| Orlando City Soccer Club | Major League Soccer | Orlando | 2013 | Inter&Co Stadium, Estadio Citrus Bowl |
| Orlando Magic | National Basketball Association | Orlando | 1989 | Amway Arena, Kia Center |
| Ottawa Senators | — | Kanata | 1992 | Canadian Tire Centre, TD Place Arena |
| Ottawa Senators | — | — | 1883 | — |
| Padres de San Diego | Grandes Ligas de Béisbol | San Diego | 1969 | Petco Park |
| Pallacanestro Ares Palermo | — | Palermo | — | — |
| Pallacanestro Aurora Desio | — | Desio | 1994 | — |
| Pallacanestro Brindisi | — | Bríndisi | 1945 | PalaPentassuglia |
| Pallacanestro Broni 93 | — | — | — | — |
| Pallacanestro Don Bosco Livorno | — | — | — | — |
| Pallacanestro Ferrara 2011 | — | Ferrara | 2011 | — |
| Pallacanestro Gallaratese | — | — | — | — |
| Pallacanestro Interclub | — | — | — | — |
| Pallacanestro Lago Maggiore | — | — | — | — |
| Pallacanestro Livorno | — | Livorno | — | — |
| Pallacanestro Lucca | — | Lucca | — | — |
| Pallacanestro Mantovana | — | Mantua | 2004 | — |
| Pallacanestro Marsala | — | — | — | — |
| Pallacanestro Messina | — | Mesina | 1976 | — |
| Pallacanestro Milano 1958 | — | Milán | 1957 | — |
| Pallacanestro Patti | — | — | — | — |
| Pallacanestro Pavia | — | Pavía | 1943 | — |
| Pallacanestro Piacentina | — | Piacenza | 2011 | — |
| Pallacanestro Pozzuoli | — | — | — | — |
| Pallacanestro Reggiana | Lega Basket Serie A | Reggio Emilia | 1974 | PalaBigi |
| Pallacanestro Sant'Antimo | — | Sant'Antimo | 1989 | — |
| Pallacanestro Senigallia | — | Senigallia | — | — |
| Pallacanestro Treviso | Lega Basket Serie A | Treviso | 1954 | Palaverde |