| Kansas City Royals | Major League Baseball | — | 1969 | Kauffman Stadium |
| KDT Nacional | Copa Perú | — | 1931 | Estadio Telmo Carbajo |
| Kleb Basket Ferrara | — | Ferrara | 2011 | — |
| LA Galaxy | Major League Soccer | Los Angeles | 1995 | Dignity Health Sports Park |
| La Loretana | Copa Perú | — | May 1971 | Estadio Aliardo Soria Pérez |
| La Peña Sporting | Copa Perú | — | April 6, 1968 | — |
| Las Vegas Raiders | National Football League | Las Vegas | 1960 | Los Angeles Memorial Coliseum, Oakland Coliseum, Allegiant Stadium |
| Latina Basket | — | Latina | 1968 | — |
| Lawn Tennis de la Exposición (fútbol) | Copa Perú | — | June 27, 1884 | National Stadium of Peru |
| Lawn Tennis F.C. | Copa Perú | — | 1995 | National Stadium of Peru |
| Legnano Knights | — | Legnano | 1966 | — |
| León de Huánuco | Peruvian Segunda División | — | 1946 | Estadio Heraclio Tapia |
| Libertas Basket Bologna | — | Bologna | — | — |
| Libertas Liburnia Basket Livorno | — | Livorno | — | — |
| Libertas Pallacanestro Forlì | — | — | — | — |
| Libertas Pallacanestro Livorno | — | Livorno | 1991 | — |
| Lima Cricket and Football Club | Copa Perú | — | 1859 | — |
| Los Angeles Angels | Major League Baseball | — | 1960 | Angel Stadium of Anaheim |
| Los Angeles Chargers | National Football League | Los Angeles | 1960 | SoFi Stadium, Dignity Health Sports Park, San Diego Stadium, Los Angeles Memorial Coliseum, Balboa Stadium |
| Los Angeles Clippers | National Basketball Association | Los Angeles | 1970 | Maple Leaf Gardens, Buffalo Memorial Auditorium, Los Angeles Memorial Sports Arena, Pechanga Arena, Crypto.com Arena |
| Los Angeles Dodgers | Major League Baseball | Los Angeles | 1884 | Dodger Stadium |
| Los Angeles FC | Major League Soccer | Los Angeles | 2014 | BMO Stadium |
| Los Angeles Kings | — | Los Angeles, Inglewood | 1967 | Crypto.com Arena, Kia Forum |
| Los Angeles Lakers | National Basketball Association | Los Angeles | 1947 | Kia Forum, Minneapolis Armory, Minneapolis Auditorium, Crypto.com Arena, Los Angeles Memorial Sports Arena |
| Los Angeles Raiders | National Football League | Los Angeles | 1982 | — |
| Los Angeles Rams | National Football League | — | 1936 | The Dome at America's Center, Angel Stadium of Anaheim, Los Angeles Memorial Coliseum, SoFi Stadium |
| Los Caimanes de Puerto Etén | Peruvian Segunda División | — | May 22, 1957 | Estadio Municipal César Flores Marigorda |
| Los Espartanos de Pacasmayo | Copa Perú | — | 1924 | — |
| Los Inseparables Sports and Cultural Club | Copa Perú | — | — | Juan Maldonado Gamarra Stadium |
| Los Tigres de Iquitos | Copa Perú | — | 2005 | Estadio Max Augustín |
| Magika Pallacanestro | — | Castel San Pietro Terme | — | — |
| Magnolia Basket Campobasso | — | Campobasso | 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 | — | — | — | — |
| Memphis Grizzlies | National Basketball Association | Memphis | 1995 | Pyramid Arena, FedExForum |
| Mens Sana Basket | Serie A | Siena | 1861 | Palasport Mens Sana |
| Mercede Basket Alghero | — | Alghero | 1977 | — |
| Merchants United Social, Sports and Cultural Association | Peruvian Primera División | — | September 19, 2002 | Juan Maldonado Gamarra Stadium |
| Miami Dolphins | National Football League | Miami | 1966 | Hard Rock Stadium |
| Miami Heat | National Basketball Association | Miami | 1988 | Miami Arena, Kaseya Center |
| Miami Marlins | Major League Baseball | — | 1993 | LoanDepot Park, Hard Rock Stadium |
| Miguel Grau de Abancay | Copa Perú | — | 1955 | Estadio Monumental de Condebamba |
| Milwaukee Braves | Major League Baseball | Milwaukee | 1953 | Milwaukee County Stadium |
| Milwaukee Brewers | Major League Baseball | Milwaukee | 1969 | American Family Field |
| Milwaukee Bucks | National Basketball Association | Milwaukee | 1968 | UW–Milwaukee Panther Arena, Bradley Center, Fiserv Forum |
| Mina San Vicente | Copa Perú | — | June 1970 | — |