| M & J Garage Door Service | Mario Enrique Acosta | — | (951) 775 3897 | Other | Murrieta · Riverside County | — | — |
| M & J Grading Services INC | Manuel De Jesus Contreras Serratos | — | (760) 601 6799 | Other | Indio · Riverside County | — | — |
| M & M Air Conditioning INC | Mitchell Ronald Kobzeff | — | (951) 672 6232 | HVAC | Menifee · Riverside County | — | — |
| M & M Cabinets | M & M Cabinets | — | (909) 522 1876 | Other | Sun City · Riverside County | — | — |
| M & M Construction Enterprises | Godofredo Martinez | info@xmmconstructionenterprisesx.com | (951) 231 4994 | GC, remodel, ADU | Corona · Riverside County | — | — |
| M & M Desert Landscape INC | Jose Antonio Magana | — | (760) 398 3000 | Windows, patio, painters | Thermal · Riverside County | — | — |
| M & M Drywall | M & M Drywall | — | (909) 289 1855 | Other | San Jacinto · Riverside County | — | — |
| M & M Framing | Jeffery Dale Miller | info@mmframing.com | (951) 471 3513 | GC, remodel, ADU | Hemet · Riverside County | — | — |
| M & M Granite Countertops INC | Miguel Angel Cano | — | (951) 245 8002 | Other | Lake Elsinore · Riverside County | — | — |
| M & M Painting | M & M Painting | — | (951) 375 8948 | Windows, patio, painters | Temecula · Riverside County | — | — |
| M & M Total Services | Dan Mihai | — | (760) 779 0736 | Electricians | Palm Desert · Riverside County | — | — |
| M & M Trenching INC | Fernando Refugio Munoz | — | (951) 660 9816 | Other | Riverside · Riverside County | — | — |
| M & S Equipment INC | Gary Francis Schones | — | (714) 325 1759 | Electricians | Riverside · Riverside County | — | — |
| M & T Electrical And All Data | Matthew Peter Rosales | — | (951) 667 5372 | Electricians | Lake Elsinore · Riverside County | — | — |
| M & Z Construction INC | Kenneth Hatfield | — | (760) 587 9672 | GC, remodel, ADU | Coachella · Riverside County | — | — |
| M - Tech Air Conditioning Services INC | Jesus Marco Aureli Araujo | — | (760) 702 5352 | HVAC | Indio · Riverside County | — | — |
| M - Tech Glass INC | Jeffery James Mitchell | — | (951) 697 4445 | Windows, patio, painters | Riverside · Riverside County | — | — |
| M A Acoustics | M A Acoustics | — | (909) 771 6833 | Other | Riverside · Riverside County | — | — |
| M A Builders | M A Builders | — | (760) 832 3998 | GC, remodel, ADU | Indio · Riverside County | — | — |
| M A Craftsman | M A Craftsman | — | (760) 902 6275 | Other | Sky Valley · Riverside County | — | — |
| M A Duarte General Contracting | Miguel Angel Duarte | — | (951) 252 3181 | GC, remodel, ADU | Murrieta · Riverside County | — | — |
| M A Electrical Contractor | Michael Aloysius Atencio | hello@maelectricalcontractor.com | (951) 316 2441 | Electricians | Norco · Riverside County | — | — |
| M A Lath & Plaster | M A Lath & Plaster | — | (760) 238 2392 | Other | Thermal · Riverside County | — | — |
| M A M Flooring Corp | Rodriguez Juan Basilio | — | (323) 434 1275 | Other | Riverside · Riverside County | — | — |
| M A N Landscape & Construction | Michael Allen Nichole | — | (909) 322 2584 | GC, remodel, ADU | La Quinta · Riverside County | — | — |
| M A Y Plumbing INC | Marcos Antonio Yescas | — | (760) 272 2691 | Other | La Quinta · Riverside County | — | — |
| M Alvarez Electric | Manuel Castillo Alvarez | — | (760) 343 0862 | Electricians | Thousand Palms · Riverside County | — | — |
| M And B Electric Co | Mark Thomas Leslie | info@mbelectric.com | (951) 757 2415 | Electricians | Temecula · Riverside County | — | — |
| M And H Construction Company INC | Romero Hector | — | (760) 403 3805 | Other | Thermal · Riverside County | — | — |
| M Art Custom Wood Design INC | Miguel Angel Sr Rodriguez | — | (951) 207 8856 | Other | Riverside · Riverside County | — | — |
| M B C Constructors Ltd | Gary Michael Morris | — | (951) 678 3374 | GC, remodel, ADU | Lake Elsinore · Riverside County | — | — |
| M B Construction | Michael Eugene Berryhill | — | (760) 578 8212 | Electricians | La Quinta · Riverside County | — | — |
| M B Painting | M B Painting | — | (951) 544 0282 | Windows, patio, painters | Hemet · Riverside County | — | — |
| M B Plumbing | M B Plumbing | — | (949) 482 8702 | Other | Riverside · Riverside County | — | — |
| M B Plumbing Air Conditioning & Heating INC | Mark Anthony Ballard | — | (951) 789 3070 | HVAC | Riverside · Riverside County | — | — |
| M Brey Incorporated DBA Mbe Construction | Matthew Artell Brey | — | (951) 845 5438 | Electricians | Beaumont · Riverside County | — | — |
| M Brock Electric Company | Mandel Brock Browning | — | (951) 201 4136 | Electricians | Hemet · Riverside County | — | — |
| M C & Associates | Steven Bryan Mc Kibban | — | (760) 930 9966 | GC, remodel, ADU | Beaumont · Riverside County | — | — |
| M C Builder Corp | Ernest Edwin Ii Casto | — | (760) 323 8010 | Windows, patio, painters | Palm Springs · Riverside County | — | — |
| M C Company | Mark Edward Cobb | — | (949) 525 7404 | GC, remodel, ADU | Palm Desert · Riverside County | — | — |