 Oklahoma City Thunder | National Basketball Association | Oklahoma City | 2008 | Climate Pledge Arena, Tacoma Dome, Paycom Center, Kingdome |
| Olimpia Basket Matera | — | Matera | 1960 | — |
| Olimpia Basket Pistoia | — | Pistoya | 1965 | — |
 Olimpia Milano | Lega Basket Serie A | Milán | 1936 | Forum di Milano |
| Olympia 68 Basketball | — | Regio de Calabria | — | — |
| Oratorio Elmas | — | — | — | — |
| Orlandina Basket | — | Capo d'Orlando | 1978 | PalaFantozzi |
 Orlando Magic | National Basketball Association | Orlando | 1989 | Amway Arena, Kia Center |
| Pallacanestro Ares Palermo | — | Palermo | — | — |
| Pallacanestro Aurora Desio | — | Desio | 1994 | — |
| Pallacanestro Biella | — | Biella | 1994 | BiellaForum |
| Pallacanestro Broni 93 | — | — | — | — |
| Pallacanestro Chieti | — | Chieti | 1989 | — |
| Pallacanestro Firenze | — | Florencia | 1948 | — |
| Pallacanestro Lago Maggiore | — | — | — | — |
| Pallacanestro Lucca | — | Lucca | — | — |
| Pallacanestro Mantovana | — | Mantua | 2004 | — |
| Pallacanestro Marsala | — | — | — | — |
| Pallacanestro Messina | — | Mesina | 1976 | — |
| Pallacanestro Milano 1958 | — | Milán | 1957 | — |
| Pallacanestro Orzinuovi | — | Orzinuovi | 1964 | — |
| Pallacanestro Patti | — | — | — | — |
| Pallacanestro Pavia | — | Pavía | 1943 | — |
| Pallacanestro Piacentina | — | Piacenza | 2011 | — |
| Pallacanestro Ribera | — | — | 1969 | — |
| Pallacanestro Sanga Milano | — | Milán | — | — |
| Pallacanestro Sant'Antimo | — | Sant'Antimo | 1989 | — |
| Pallacanestro Treviso | Lega Basket Serie A | Treviso | 1954 | Palaverde |
| Pallacanestro Trieste | Lega Basket Serie A | Trieste | 1975 | Palatrieste |
 Pallacanestro Varese | Lega Basket Serie A | Varese | 1945 | PalaWhirlpool |
| Pallacanestro Virtus Cassino | — | Frosinone | 2011 | — |
| Palmares Catania | — | Catania | — | — |
| Pantere Basket Femminile | — | — | — | — |
| Partenio Avellino | — | — | — | — |
| Partenope Napoli Basket | — | Sant'Antimo | 1957 | — |
| PCR Messina | — | Mesina | — | — |
| Pescara Basket | Serie C (Italian men's basketball league) | Pescara | — | PalaElettra |
| Petrarca Armistizio Patavium | — | Padua | 1934 | — |
 PF Schio | — | Schio | 1973 | — |
 Philadelphia 76ers | National Basketball Association | Filadelfia | 1946 | Xfinity Mobile Arena, Toyota Coliseum, Philadelphia Arena, The Spectrum, Philadelphia Convention Hall and Civic Center, Oncenter War Memorial Arena |
 Phoenix Suns | National Basketball Association | Phoenix | 1968 | Arizona Veterans Memorial Coliseum, Footprint Center |
| Pistoia Basket 2000 | Lega Basket Serie A | Pistoya | 2000 | PalaFermi |
| PMS Basketball | — | Moncalieri | — | — |
| PMS Torino | Lega Basket Serie A | Turín | 2009 | — |
| Poderosa Basket Montegranaro | — | Montegranaro | 1993 | — |
| Polisportiva Cervia Milano Marittima | — | — | — | — |
| Polisportiva Folgore Nocera | — | — | — | — |
 Portland Trail Blazers | National Basketball Association | Portland | 1970 | Veterans Memorial Coliseum, Moda Center |