| Marvin Concrete INC | Dustin Lee Marvin | — | (951) 704 4245 | Other | Temecula · Riverside County | — | — |
| Marvin Hawley | Marvin Hawley | — | (760) 409 3055 | GC, remodel, ADU | Indio · Riverside County | — | — |
| Marvin Investments INC | Wells Linden Marvin | — | (650) 492 1762 | GC, remodel, ADU | La Quinta · Riverside County | — | — |
| Marvin Jordan Construction | Marvin Lee Jordan | — | (760) 485 0991 | GC, remodel, ADU | La Quinta · Riverside County | — | — |
| Marvin Rodriguez Corp | Alexander Calep Rodriguez | — | (951) 249 6847 | Pool | Cathedral City · Riverside County | — | — |
| Marwan Slman Alabbasi | Marwan Slman Alabbasi | — | (951) 776 9300 | GC, remodel, ADU | Perris · Riverside County | — | — |
| Mary Sue Nunnally | Mary Sue Nunnally | — | (951) 343 0092 | Other | Riverside · Riverside County | — | — |
| Mascorro Concrete Construction INC | Santiago Garcia Mascorro | — | (760) 343 1243 | Other | Thousand Palms · Riverside County | — | — |
| Masonry Design | Masonry Design | — | (951) 489 9562 | Other | Palm Desert · Riverside County | — | — |
| Masonry Solutions | Catherine Elizabeth Echeverria | contact@masonrysolutions.com | (951) 536 3211 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Massive Audio Video | Massive Audio Video | — | (951) 663 6054 | Other | Banning · Riverside County | — | — |
| Massivo Roofing INC | Valle Jose Bernal | jesus@massivoroofing.com | (619) 227 4340 | Other roofers | Menifee · Riverside County | — | — |
| Master Advantage Remodels | Master Advantage Remodels | — | (760) 848 6557 | GC, remodel, ADU | Cathedral City · Riverside County | — | — |
| Master Air Tech | Torres Ramon Ramirez | ramon@masterairtech.com | (909) 749 6065 | HVAC | Moreno Valley · Riverside County | — | — |
| Master Craftsman | Master Craftsman | — | (619) 861 2455 | GC, remodel, ADU | Wildomar · Riverside County | — | — |
| Master Elite Plumbing | Master Elite Plumbing | — | (760) 989 7023 | Other | Indio · Riverside County | — | — |
| Master Landscape Co | Fernando Morales Mendez | — | (951) 652 1536 | Windows, patio, painters | Hemet · Riverside County | — | — |
| Master Overhead Door Co | Juan Alberto Granados | — | (760) 272 4011 | Other | Indio · Riverside County | — | — |
| Master Pools INC DBA Master Pools & Spas | Stephen Richard Hanousek | — | (760) 346 6115 | Pool | Indio · Riverside County | — | — |
| Master Pro Stucco & Lath | Eduardo Daniel Bermejo Martinez | — | (951) 905 4191 | Other | Lake Elsinore · Riverside County | — | — |
| Master Repair Electric | Salvador Sanchez Barriga | — | (760) 698 1982 | Electricians | Coachella · Riverside County | — | — |
| Master Restoration & Construction INC | Costy Jr Borcsa | — | (951) 941 3788 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Master Roofing By Amaya | Martin Jr Amaya | — | (951) 581 1315 | Other roofers | Perris · Riverside County | — | — |
| Master Roofing LLC | Mark Adam Cardenas | — | (951) 662 6765 | Other roofers | Riverside · Riverside County | — | — |
| Master Tile INC | Rosas Alvino Bravo | — | (714) 493 2439 | Other | Riverside · Riverside County | — | — |
| Master's Electrical Work Solutions | Jorge Manuel Navarro | — | (909) 452 5092 | Electricians | Riverside · Riverside County | — | — |
| Mastercare Landscape | Francisco Bautista-Carmona | — | (760) 609 6478 | Windows, patio, painters | Indio · Riverside County | — | — |
| Mastercraft Tile And Marble | Mastercraft Tile And Marble | — | (714) 501 2515 | Windows, patio, painters | Corona · Riverside County | — | — |
| Masterflow Plumbing And Drain | Juan Francisco Prieto | — | (916) 547 9747 | Other | Murrieta · Riverside County | — | — |
| Mastermind Electric | Eric Giovanni Lujano | steve@mastermindelectric.com | (714) 322 7846 | Electricians | Riverside · Riverside County | — | — |
| Masterpiece Floor N Wall | Masterpiece Floor N Wall | — | (951) 710 4113 | Other | Lake Elsinore · Riverside County | — | — |
| Masters Of Moulding LLC | David Frank Zaita | — | (951) 375 6026 | Other | Murrieta · Riverside County | — | — |
| Masters Pro Coatings INC | Narvaez Juan Perez | — | (951) 805 1359 | Windows, patio, painters | Wildomar · Riverside County | — | — |
| Mastersplit HVAC | Mastersplit HVAC | — | (562) 504 9355 | HVAC | Desert Hot Springs · Riverside County | — | — |
| Mat Millworks | Mat Millworks | — | (562) 726 5260 | Other | Beaumont · Riverside County | — | — |
| Mata INC | Carlos Francisco Mata | — | (760) 554 5548 | Electricians | Riverside · Riverside County | — | — |
| Mata Tile | Mata Tile | — | (562) 659 4480 | Other | Corona · Riverside County | — | — |
| Matamoros Construction INC | Eleodoro Alfredo Matamoros Martel | — | (909) 787 5772 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| Matcon General Engineering INC | Randy Dean Matthews | — | (951) 751 8271 | Other | Corona · Riverside County | — | — |
| Mathey Quality Construction | Jason Lee Mathey | — | (951) 537 8241 | GC, remodel, ADU | San Jacinto · Riverside County | — | — |