| New Orleans Pelicans | National Basketball Association | New Orleans | 2002 | Paycom Center, Smoothie King Center |
| New Orleans Saints | Liga Nasional Sepak bola Amerika | — | 1967 | Caesars Superdome |
| New York City FC | Liga Utama Sepak Bola Amerika Serikat | Kota New York | 21 Mei 2013 | Stadion Yankee |
| New York Giants | Liga Nasional Sepak bola Amerika | Wilayah metropolitan New York | 1925 | Stadion MetLife |
| New York Giants | — | — | — | — |
| New York Islanders | — | Brooklyn, Elmont, Uniondale | 1972 | UBS Arena, Barclays Center, Nassau Veterans Memorial Coliseum |
| New York Jets | Liga Nasional Sepak bola Amerika | Kota New York, East Rutherford | 1960 | Stadion MetLife |
| New York Knicks | National Basketball Association | Kota New York | 1946 | Madison Square Garden, Madison Square Garden, 69th Regiment Armory |
| New York Mets | Major League Baseball | — | 1962 | Citi Field |
| New York Rangers | — | Manhattan | 1926 | Madison Square Garden, Madison Square Garden |
| New York Red Bulls | Liga Utama Sepak Bola Amerika Serikat | Harrison | 1995 | Stadion Giants, Red Bull Arena |
| New York Yankees | Major League Baseball | The Bronx | 1903 | Yankee Stadium, Stadion Yankee, Hilltop Park, Shea Stadium, Polo Grounds |
| Nova Virtus Ragusa | — | Ragusa, Italia | — | — |
| NPC Rieti | — | Rieti | 2011 | — |
| Nuova Fiamma Stabia | — | — | — | — |
| Nuova Pallacanestro Gorizia | — | Gorizia | 1934 | — |
| Nuova Pallacanestro Vigevano | — | Vigevano | 1955 | — |
| Oakland Athletics | Major League Baseball | Oakland | 1968 | Coliseum RingCentral |
| OBG Roma | — | — | — | — |
| Octavio Espinosa de Ica | Copa Perú | — | 1923 | Estadio José Picasso Peratta |
| Oklahoma City Thunder | National Basketball Association | Kota Oklahoma | 2008 | Climate Pledge Arena, Tacoma Dome, Paycom Center, Kingdome |
| Oleggio Magic Basket | — | Oleggio | — | — |
| Olimpia Basket Matera | — | Matera | 1960 | — |
| Olimpia Basket Pistoia | — | Pistoia | 1965 | — |
| Olimpia Milano | Lega Basket Serie A | Milan | 1936 | Forum Mediolanum |
| Olympia 68 Basketball | — | Reggio di Calabria | — | — |
| Olímpico Peruano | Copa Perú | — | 2 Februari 1945 | — |
| Oratorio Elmas | — | — | — | — |
| Orlando City SC | Liga Utama Sepak Bola Amerika Serikat | Orlando | 2013 | Stadion Exploria, Stadion Camping World |
| Orlando Magic | National Basketball Association | Orlando | 1989 | Amway Arena, Kia Center |
| Orzi Basket | — | Orzinuovi | 1964 | — |
| Ottawa Senators | — | Kanata | 1992 | Canadian Tire Centre, TD Place Arena |
| Ottawa Senators | — | — | 1883 | — |
| Pallacanestro Biella | — | Biella | 1994 | BiellaForum |
| Pallacanestro Brescia | Lega Basket Serie A | Brescia | 2009 | PalaLeonessa |
| Pallacanestro Brindisi | — | Brindisi | 1945 | PalaPentassuglia |
| Pallacanestro Chieti | — | Chieti | 1989 | — |
| Pallacanestro Don Bosco Livorno | — | — | — | — |
| Pallacanestro Femminile Costone | — | — | — | — |
| Pallacanestro Gallaratese | — | — | — | — |
| Pallacanestro Interclub | — | — | — | — |
| Pallacanestro Lago Maggiore | — | — | — | — |
| Pallacanestro Livorno | — | Livorno | — | — |
| Pallacanestro Lucca | — | Lucca | — | — |
| Pallacanestro Mantovana | — | Mantova | 2004 | — |
| Pallacanestro Milano 1958 | — | Milan | 1957 | — |
| Pallacanestro Patti | — | — | — | — |
| Pallacanestro Petrarca Padova | — | Padova | 1934 | — |