| M&m Drywall & Taping | Miguel Angel Sr Cisneros-Gonzalez | — | (760) 698 3735 | Other | Indio · Riverside County | — | — |
| M&m Elite Roofing Co | Santos Anthony Gonzalez | — | (909) 306 8788 | Other roofers | Moreno Valley · Riverside County | — | — |
| M&m Heating And Air Conditioning INC | Angela Christine Labuda | — | (951) 258 6898 | HVAC | Blythe · Riverside County | — | — |
| M&m Landscape INC | Martin Franco | — | (951) 833 0478 | Windows, patio, painters | Lake Elsinore · Riverside County | — | — |
| M&t Glass Services | Miguel Hernandez | — | (562) 353 0983 | Windows, patio, painters | Moreno Valley · Riverside County | — | — |
| M's Electric | Malik Aslo Taylor | — | (760) 421 2788 | Electricians | Temecula · Riverside County | — | — |
| M-lite Electric INC | Marco Mariscal | — | (909) 993 2666 | Electricians | Norco · Riverside County | — | — |
| M. Rivera Roofing INC | Martin Rivera Ruiz | — | (760) 902 9781 | Other roofers | Cathedral City · Riverside County | — | — |
| M1 Plastering | M1 Plastering | — | (760) 464 5808 | Other | Thermal · Riverside County | — | — |
| M3 Grading And Excavation INC | Joseph Martin Bocanegra | — | (951) 570 3936 | Other | Menifee · Riverside County | — | — |
| M3w Demolition INC | Michael Robert Winfrey | — | (442) 390 9876 | Other | Temecula · Riverside County | — | — |
| Ma Granite Construction INC | Marya Gisela Arredondo Hicks | — | (909) 376 7075 | GC, remodel, ADU | Norco · Riverside County | — | — |
| Mac Drywall | Mac Drywall | — | (323) 399 5140 | Other | Thermal · Riverside County | — | — |
| Mac's Electrical | Michael Anthony Jr Cervantes | — | (951) 210 3983 | Electricians | Riverside · Riverside County | — | — |
| Mac's Property Services | Richard Jr Maciel | — | (714) 328 5298 | GC, remodel, ADU | Murrieta · Riverside County | — | — |
| Maccen Construction | Nicholas Alexander Swanson | — | (909) 212 3000 | GC, remodel, ADU | Eastvale · Riverside County | — | — |
| Macdonald Electric INC DBA T & C Electric | Thomas Michael Macdonald | — | (951) 272 3848 | Electricians | Corona · Riverside County | — | — |
| Macedo Insulation INC | David Michael Deridder | — | (951) 660 1936 | Other | Nuevo · Riverside County | — | — |
| Macias Construction | Macias Vicente | — | (714) 412 5898 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Macias Plumbing & Rooter | Macias Plumbing & Rooter | — | (310) 968 8983 | Other | Cathedral City · Riverside County | — | — |
| Macias Plumbing Mechanical | Macias Plumbing Mechanical | — | (323) 289 4936 | Other | Perris · Riverside County | — | — |
| Macias Refrigeration INC | Jorge Macias | info@maciasrefrigeration.com | (951) 687 3006 | HVAC | Riverside · Riverside County | — | — |
| Maciel Estates Construction | Cameron Ty Maciel | — | (951) 312 0408 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| Maciel Landscape | Maciel Landscape | — | (760) 275 8034 | Windows, patio, painters | Cathedral City · Riverside County | — | — |
| Mack Construction & Equipment Company | Dean Allen Mack | — | (951) 674 1267 | GC, remodel, ADU | Wildomar · Riverside County | — | — |
| Mack P And S Construction Incorporated | Dean Allen Mack | — | (951) 674 1267 | GC, remodel, ADU | Wildomar · Riverside County | — | — |
| Mack Rebar INC | Kelly Marie Williams | — | (562) 706 4715 | Other | Corona · Riverside County | — | — |
| Macklin Mirror & Glass | Macklin Mirror & Glass | — | (760) 574 3487 | Windows, patio, painters | Palm Desert · Riverside County | — | — |
| Maco Equipment Rentals INC | David Brent Ii Mc Farland | — | (760) 343 5622 | Other | Thousand Palms · Riverside County | — | — |
| Macro Mechanical INC | Marc Alan Crofut | gbridges@macromechanical.com | (951) 677 6227 | HVAC | Murrieta · Riverside County | — | — |
| Macs A Million Painting | Rodolfo Robles | — | (714) 366 4269 | Windows, patio, painters | Corona · Riverside County | — | — |
| Macs Tree Service INC | Jeffrey Andrew Mc Elrath | — | (951) 678 1248 | GC, remodel, ADU | Wildomar · Riverside County | — | — |
| Mad Countertops | Mad Countertops | — | (951) 430 9040 | Other | Canyon Lake · Riverside County | — | — |
| Mad Electric Construction INC | Monica Rae Stalford | — | (951) 489 8563 | Electricians | Hemet · Riverside County | — | — |
| Maddco Drywall Contractors INC | Alejandro Becerra | — | (909) 486 8697 | Windows, patio, painters | Cherry Valley · Riverside County | — | — |
| Maddox Concrete INC | Andre Rene Maddox | — | (951) 830 7120 | Other | Corona · Riverside County | — | — |
| Madison Ave Computer Services INC | Michael Joseph Adornetto | — | (949) 230 2359 | Other | Corona · Riverside County | — | — |
| Madrid Concrete Contractors | Michael Anthony Ii Madrid | — | (951) 674 6241 | Other | Lake Elsinore · Riverside County | — | — |
| Madrigal Cabinets LLC | Ernesto Madrigal | — | (909) 904 3674 | Other | Jurupa Valley · Riverside County | — | — |
| Madrigal Construction INC | Rick Madrigal | — | (909) 762 1018 | GC, remodel, ADU | Nuevo · Riverside County | — | — |