| No | Entrant | Races | Active Years |
|---|
| 454 | M. Pete Wales (Indy only) | 2 |
1950, 1955 |
| 455 | M.A. Walker (Indy only) | 3 |
1950–1951, 1953 |
| 456 | Maki Engineering | 8 |
1974–1976 |
| 457 | Manor Marussia F1 Team | 19 |
2015 |
| 458 | Manor Racing MRT | 21 |
2016 |
| 459 | Mapfre-Williams | 1 |
1976 |
| 460 | Marcel Balsa | 1 |
1952 |
| 461 | March Engineering | 43 |
1970, 1974–1976 |
| 462 | March F1 | 16 |
1992 |
| 463 | March Grand Prix Team | 16 |
1981–1982 |
| 464 | March Racing | 15 |
1976 |
| 465 | March Racing Team | 3 |
1973 |
| 466 | Maria-Teresa de Filippis | 3 |
1958 |
| 467 | Mario Deliotti Racing | 1 |
1978 |
| 468 | Marlboro BRM | 27 |
1972–1973 |
| 469 | Marlboro McLaren | 16 |
1993 |
| 470 | Marlboro McLaren International | 109 |
1981–1987 |
| 471 | Marlboro McLaren Mercedes | 33 |
1995–1996 |
| 472 | Marlboro McLaren Peugeot | 16 |
1994 |
| 473 | Marlboro Team Alfa Romeo | 60 |
1980–1983 |
| 474 | Marlboro Team McLaren | 77 |
1976–1980 |
| 475 | Marlboro Team Texaco | 29 |
1974–1975 |
| 476 | Martini Racing | 47 |
1975–1977 |
| 477 | Martini Racing Team | 13 |
1972–1973 |
| 478 | Martini Racing Team Lotus | 15 |
1979 |
| 479 | Marussia F1 Team | 55 |
2012–2014 |
| 480 | Marussia Virgin Racing | 19 |
2011 |
| 481 | Maserati Race Cars (Indy only) | 1 |
1951 |
| 482 | Mastercard Lola F1 Team | 1 |
1997 |
| 483 | Matra International | 23 |
1968–1969 |
| 484 | Matra Sports | 14 |
1967–1968 |
| 485 | Maurice Trintignant | 5 |
1964 |
| 486 | McLaren F1 Team | 59 |
2018–2020 |
| 487 | McLaren Honda | 39 |
2015, 2017 |
| 488 | McLaren Honda Formula 1 Team | 21 |
2016 |
| 489 | McLaren Mercedes | 19 |
2014 |
| 490 | Meiritsu Racing Team | 1 |
1977 |
| 491 | Mel B. Wiggers (Indy only) | 2 |
1952, 1954 |
| 492 | Melchester Racing | 2 |
1977–1978 |
| 493 | Memphis International Team Surtees | 1 |
1974 |
| 494 | Mercedes AMG Petronas F1 Team | 135 |
2012–2017, 2020 |
| 495 | Mercedes AMG Petronas Motorsport | 42 |
2018–2019 |
| 496 | Mercedes GP Petronas F1 Team | 38 |
2010–2011 |
| 497 | Merz Engineering Inc (Indy only) | 1 |
1955 |
| 498 | Midland F1 Racing | 15 |
2006 |
| 499 | Mike Fisher | 2 |
1967 |
| 500 | Mike Harris | 1 |
1962 |
| 501 | Miklos Sperling (Indy only) | 1 |
1954 |
| 502 | Mild Seven Benetton Ford | 16 |
1994 |
| 503 | Mild Seven Benetton Playlife | 49 |
1998–2000 |
| 504 | Mild Seven Benetton Renault | 67 |
1995–1997, 2001 |
| 505 | Mild Seven Renault F1 Team | 88 |
2002–2006 |
| 506 | Milt Marion (Indy only) | 1 |
1950 |
| 507 | Minardi Cosworth | 18 |
2004 |
| 508 | Minardi F1 Team | 19 |
2005 |
| 509 | Minardi Scuderia Italia | 33 |
1994–1995 |
| 510 | Minardi Team | 145 |
1985–1987, 1989, 1991–1993, 1996–1997 |
| 511 | Modena Team SpA | 16 |
1991 |
| 512 | Momo Corporation | 1 |
1961 |
| 513 | Moneytron Onyx Formula One | 23 |
1989–1990 |
| 514 | Monte Carlo Auto Sport | 1 |
1959 |
| 515 | Monteverdi Onyx Formula One | 3 |
1990 |
| 516 | Motor Presse Verlag | 1 |
1952 |
| 517 | Motor Racers Inc (Indy only) | 1 |
1954 |
| 518 | Motor Racing Developments | 109 |
1969–1974, 1989–1990 |
| 519 | Motor Racing Developments Ltd | 75 |
1985–1987, 1991–1992 |
| 520 | MRD International | 16 |
1984 |
| 521 | MTV Simtek Ford | 21 |
1994–1995 |
| 522 | Murrell Belanger (Indy only) | 7 |
1950–1956 |
