| Magnolia Basket Campobasso | — | काम्पोबास्सो | 2017 | — |
| Mariscal Miller | Copa Perú | — | — | Estadio Jorge Basadre |
| Mariscal Nieto de Ilo | Copa Perú | — | — | Estadio Mariscal Nieto |
| Mariscal Sucre | — | — | 1925 | National Stadium of Peru |
| Maurolico Messina | — | — | — | — |
| Maxima Roma | Serie A | — | 2026 | Palazzo dello Sport |
| Mens Sana Basket | Serie A | सियेना | 1861 | Palasport Mens Sana |
| Mercede Basket Alghero | — | अल्गेरो | 1977 | — |
| Merchants United Social, Sports and Cultural Association | Peruvian Primera División | — | 19 सितंबर 2002 | Juan Maldonado Gamarra Stadium |
| Miguel Grau de Abancay | Copa Perú | — | 1955 | Estadio Monumental de Condebamba |
| Milwaukee Braves | मेजर लीग बेसबॉल | मिल्वौकी | 1953 | Milwaukee County Stadium |
| Mina San Vicente | Copa Perú | — | जून 1970 | — |
| Minnesota United FC | मेजर लीग सॉकर | मिनियापोलिस | 2015 | Allianz Field, Huntington Bank Stadium |
| Miraflores Sporting Club | — | — | — | Estadio Nacional del Perú (1897) |
| Modena Basket | — | — | — | — |
| Montigarda Basket | — | Montichiari | — | — |
| Montreal Expos | मेजर लीग बेसबॉल | — | 1969 | Olympic Stadium, Jarry Park Stadium |
| Montreal Maroons | — | — | 1924 | Montreal Forum |
| Napoli Basket | — | नेपल्स | 1978 | — |
| Napoli Basket | Serie A | नेपल्स | 2016 | PalaBarbuto |
| Napoli Basket Vomero | — | नेपल्स | 1986 | — |
| Napoli Basketball | — | नेपल्स | 2011 | — |
| Nashville SC | मेजर लीग सॉकर | नैशविले | 2017 | Geodis Park, एल पी फील्ड |
| New Basket Brindisi | Serie A | ब्रिंदिज़ी | 1992 | PalaPentassuglia |
| New Polibasket San Bonifacio | — | — | — | — |
| New York Giants | — | — | — | — |
| NPC Rieti | — | Rieti | 2011 | — |
| Nuova AMG Sebastiani Basket Napoli | — | Rieti | 1946 | — |
| Nuova Pallacanestro Vigevano | — | Vigevano | 1955 | — |
| OBG Roma | — | — | — | — |
| Octavio Espinosa de Ica | Copa Perú | — | 1923 | Estadio José Picasso Peratta |
| Oklahoma City Thunder | नेशनल बास्केटबॉल असोसिएशन | ओक्लाहामा सिटी | 2008 | Climate Pledge Arena, Tacoma Dome, Paycom Center, Kingdome |
| Oleggio Magic Basket | — | Oleggio | — | — |
| Olimpia Basket Matera | — | मटेरा | 1960 | — |
| Olimpia Milano | Serie A | मिलानो | 1936 | Forum di Milano |
| Olympia 68 Basketball | — | रेज्जो कालाब्रिया | — | — |
| Olímpico Peruano | Copa Perú | — | 2 फ़रवरी 1945 | — |
| Orlandina Basket | — | Capo d'Orlando | 1978 | PalaFantozzi |
| Orzi Basket | — | Orzinuovi | 1964 | — |
| Ottawa Senators | — | — | 1883 | — |
| Pallacanestro Ares Palermo | — | पलेर्मो | — | — |
| Pallacanestro Aurora Desio | — | Desio | 1994 | — |
| Pallacanestro Biella | — | बीएलला | 1994 | BiellaForum |
| Pallacanestro Brindisi | — | ब्रिंदिज़ी | 1945 | PalaPentassuglia |
| Pallacanestro Broni 93 | — | — | — | — |
| Pallacanestro Chieti | — | Chieti | 1989 | — |
| Pallacanestro Don Bosco Livorno | — | — | — | — |
| Pallacanestro Femminile Costone | — | — | — | — |