| Mecca Pacific Concrete & Design | Mecca Pacific Concrete & Design | — | (760) 600 1522 | Other | Coachella · Riverside County | — | — |
| Mechanical Air Control INC | David Paul Hoffman | — | (951) 352 9832 | HVAC | Riverside · Riverside County | — | — |
| Mechanical Mciver | Mechanical Mciver | — | (951) 809 3982 | HVAC | Riverside · Riverside County | — | — |
| Mechanical Pros Heating And Air Conditioning INC | Daniel John Jaramillo | — | (951) 440 5619 | HVAC | Temecula · Riverside County | — | — |
| Mechanical Ventilation Systems | Mechanical Ventilation Systems | — | (951) 675 1303 | HVAC | Banning · Riverside County | — | — |
| Medearis Construction Company | Darlene Bernice Medearis | jaredtomseth@gmail.com | (951) 348-7699 | GC, remodel, ADU | Temecula · Riverside County | — | — |
| Medero Plumbing Services | Julio Cesar Medero | — | (213) 425 6757 | Other | Lake Elsinore · Riverside County | — | — |
| Medina Builders | Reynaldo Medina | scimedinaohio@gmail.com | (951) 515 5401 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Medina Plumbing & Rooter | Medina Plumbing & Rooter | — | (951) 201 7015 | Other | Riverside · Riverside County | — | — |
| Medina Renovation & Construction INC | Mauricio Alejandro Medina | — | (951) 623 4966 | GC, remodel, ADU | Murrieta · Riverside County | — | — |
| Medina's Framing | Francisco Javier Medina | — | (951) 252 9555 | Other | Hemet · Riverside County | — | — |
| Medina-zendejas Communications INC | Marcos Medina | — | (714) 341 2931 | Other | Moreno Valley · Riverside County | — | — |
| Meek Electric LLC | Joseph Allen Langley | — | (951) 315 1467 | Electricians | Thermal · Riverside County | — | — |
| Meeks Electric INC | Harold Edwin Iii Meeks | — | (909) 556 1003 | Electricians | Riverside · Riverside County | — | — |
| Meera Builder | Meera Builder | — | (714) 488 0460 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Mega General Construction INC | Eddy Jesus Perez Perez | — | (714) 855 5147 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| Mega Sun Pools INC | Jeremy Ray Parsons | — | (760) 501 6422 | Pool | Palm Desert · Riverside County | — | — |
| Megawatt Energy Electric | Joseph Raymond Herle | — | (951) 409 4063 | Electricians | Lake Elsinore · Riverside County | — | — |
| Mehdi Hosseinzadeh | Mehdi Hosseinzadeh | — | (310) 906 8825 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Meineke & Son's Electrical Services | Brian Jay Meineke | — | (951) 232 9248 | Electricians | Wildomar · Riverside County | — | — |
| Meineke Electric | Spencer Ryan Meineke | — | (951) 232 5940 | Electricians | Menifee · Riverside County | — | — |
| Mejia Construction | Joseph Francis Mejia | — | (951) 813 0042 | GC, remodel, ADU | Murrieta · Riverside County | — | — |
| Mekhael Alfarhat | Mekhael Alfarhat | — | (714) 936 6550 | Other | Eastvale · Riverside County | — | — |
| Melendez Mechanical | Melendez Mechanical | — | (951) 836 0758 | HVAC | Lake Elsinore · Riverside County | — | — |
| Melendez Tile Company | Jose Luis Melendez | — | (760) 415 6376 | Other | Temecula · Riverside County | — | — |
| Melissa Mcguinness | Melissa Mcguinness | — | (562) 805 6329 | GC, remodel, ADU | Norco · Riverside County | — | — |
| Mellor Electric INC | Christopher Lee Mellor | — | (951) 719 4294 | Electricians | Menifee · Riverside County | — | — |
| Melo Pools INC | Vasthy Gina Melo | — | (760) 341 3505 | Pool | Palm Desert · Riverside County | — | — |
| Melvin's Flooring | Melvin Estuardo Gregorio Perez | — | (951) 286 7338 | Other | Moreno Valley · Riverside County | — | — |
| Memo's Plumbing | Memo's Plumbing | — | (760) 619 0564 | Other | Indio · Riverside County | — | — |
| Memos Flooring Installations | Guillermo Roman | — | (951) 203 7414 | Other | Menifee · Riverside County | — | — |
| Menasco Air Conditioning Service | Eric Matthew Menasco | — | (951) 201 5578 | HVAC | Moreno Valley · Riverside County | — | — |
| Mendez Air Conditioning & Heating | Enrique Jr Mendez | — | (760) 343 5041 | HVAC | Thousand Palms · Riverside County | — | — |
| Mendez Home Renovations INC | Jose Martin Mendez-Chavez | — | (626) 347 2813 | GC, remodel, ADU | Jurupa Valley · Riverside County | — | — |
| Mendoza Concrete Construction | Mendoza Carranza Isac | — | (760) 989 3400 | Other | Coachella · Riverside County | — | — |
| Mendoza Electric INC | Mendoza Cesar | — | (760) 404 7214 | Electricians | Indio · Riverside County | — | — |
| Mendoza Engineering | Mendoza Engineering | — | (951) 237 9389 | Other | Perris · Riverside County | — | — |
| Mendoza Fire Protection LLC DBA Dm And Sons Fire Protection | David Rafael Mendoza | — | (951) 543 1638 | Other | Temecula · Riverside County | — | — |
| Mendoza Painting | Mendoza Painting | — | (760) 610 3167 | Windows, patio, painters | Thermal · Riverside County | — | — |
| Mendoza Quality Construction | Jorge Josue Mendoza | — | (760) 421 2138 | GC, remodel, ADU | Menifee · Riverside County | — | — |